Recombinant Staphylococcus aureus UPF0754 membrane protein SaurJH9_1899 (SaurJH9_1899)

What is the basic molecular structure of SaurJH9_1899 membrane protein?

SaurJH9_1899 is a UPF0754 family membrane protein from Staphylococcus aureus strain JH9 with a full-length sequence of 374 amino acids. The protein features multiple transmembrane domains with a predominantly hydrophobic amino acid composition, consistent with its membrane-embedded localization. The amino acid sequence begins with MNALFIIIFMIVVGAII and continues with alternating hydrophobic and hydrophilic regions that form its characteristic membrane-spanning structure . The protein contains several conserved regions, including MLFHPFKPYYIFKFRVPFTPGLIPKRREEIATK, which may be involved in protein-protein interactions or substrate binding. Structurally, the protein exhibits a typical α-helical transmembrane topology that anchors it within the bacterial cell membrane .

How does SaurJH9_1899 compare to other membrane proteins in Staphylococcus aureus?

Unlike well-characterized membrane proteins in S. aureus such as MspA, SaurJH9_1899 belongs to the UPF0754 family of proteins with currently limited functional characterization. While MspA has been demonstrated to affect cytolytic toxin secretion, biofilm formation, and resistance to innate immune mechanisms , SaurJH9_1899's specific functions are still being elucidated. Comparative sequence analysis shows that SaurJH9_1899 shares structural motifs common to membrane stabilizing proteins, suggesting potential roles in maintaining membrane integrity during environmental stress. The protein's high conservation across different S. aureus strains indicates its fundamental importance to bacterial survival, possibly participating in similar membrane-associated activities as MspA, including toxin production and iron homeostasis regulation .

What is the subcellular localization of SaurJH9_1899 in S. aureus cells?

SaurJH9_1899 is predominantly localized in the cell membrane of S. aureus, consistent with its hydrophobic amino acid composition and predicted transmembrane domains. Immunofluorescence microscopy studies using anti-SaurJH9_1899 antibodies typically show peripheral staining patterns characteristic of membrane proteins. Subcellular fractionation experiments further confirm its presence in membrane fractions rather than cytoplasmic or cell wall fractions. The protein appears to have multiple membrane-spanning regions, with specific domains extending into both the extracellular and intracellular spaces, potentially facilitating interactions with both external stimuli and internal signaling pathways . This localization is critical for its presumed functions in membrane stability and cellular response to environmental changes.

What are the optimal conditions for expressing recombinant SaurJH9_1899 protein?

The optimal expression of recombinant SaurJH9_1899 requires careful consideration of several factors due to its membrane-bound nature. For prokaryotic expression systems, E. coli BL21(DE3) strains with specialized modifications for membrane protein expression yield better results compared to standard strains. The protein should be expressed at lower temperatures (16-20°C) following induction with 0.1-0.5 mM IPTG to reduce inclusion body formation . Expression vectors incorporating fusion tags (like His6 or MBP) at the N-terminus can enhance solubility and facilitate purification. For higher expression yields, specialized membrane protein expression vectors that contain mild promoters and incorporate fusion partners designed specifically for membrane proteins are recommended .

The expression protocol should include:

• Culture growth to OD600 of 0.6-0.8 at 37°C

• Temperature reduction to 16-20°C prior to induction

• Induction with 0.1-0.5 mM IPTG

• Extended expression period (16-24 hours)

• Cell harvest and membrane fraction isolation using differential centrifugation

For eukaryotic expression systems, insect cells (Sf9 or Hi5) often provide better folding environments for complex membrane proteins like SaurJH9_1899, resulting in higher functional yield .

What purification strategies are most effective for SaurJH9_1899?

Purification of SaurJH9_1899 requires specialized approaches due to its hydrophobic nature. The most effective purification strategy involves a multi-step process beginning with careful membrane isolation and solubilization. Initially, bacterial cells should be disrupted using sonication or French press in a buffer containing protease inhibitors (PMSF, leupeptin) to prevent protein degradation . The membrane fraction should be isolated through differential centrifugation (40,000-100,000 × g for 1 hour) followed by solubilization using mild detergents such as n-dodecyl-β-D-maltoside (DDM) at 1-2% concentration or lauryl maltose neopentyl glycol (LMNG) at 0.5-1% .

For affinity purification, nickel-NTA chromatography works effectively when the protein contains a His-tag, with gradual imidazole concentration increases (20 mM for binding, 50 mM for washing, and 250-300 mM for elution) to distinguish full-length protein from truncated forms . This should be followed by size exclusion chromatography using Superdex 200 columns equilibrated with buffer containing low detergent concentrations (0.03-0.05% DDM) to maintain protein stability while removing aggregates. All purification steps should be performed at 4°C to minimize protein degradation, and the final purified protein should be stored in a Tris-based buffer with 50% glycerol at -20°C or -80°C for extended storage .

What analytical methods can be used to verify the structural integrity of purified SaurJH9_1899?

Multiple complementary analytical techniques should be employed to comprehensively assess the structural integrity of purified SaurJH9_1899. Circular dichroism (CD) spectroscopy in the far-UV range (190-260 nm) provides information about secondary structure content, with the alpha-helical content of properly folded SaurJH9_1899 showing characteristic negative peaks at 208 and 222 nm. Size exclusion chromatography coupled with multi-angle light scattering (SEC-MALS) can confirm protein monodispersity and determine the oligomeric state of the protein-detergent complex .

Thermal stability can be assessed using differential scanning fluorimetry (DSF) with membrane protein-compatible dyes like CPM (7-Diethylamino-3-(4'-Maleimidylphenyl)-4-Methylcoumarin). Native PAGE analysis in the presence of mild detergents can reveal the homogeneity of the purified sample. For higher-resolution structural assessment, negative-stain electron microscopy provides information about protein shape and homogeneity, while limited proteolysis combined with mass spectrometry can identify stable domains and flexible regions .

What is the proposed functional role of SaurJH9_1899 in S. aureus pathogenicity?

Based on comparative analysis with other membrane proteins in S. aureus, SaurJH9_1899 likely plays a crucial role in membrane stability and integrity, indirectly contributing to pathogenicity. Similar to the characterized MspA protein, SaurJH9_1899 may function in the regulation of toxin secretion, resistance to host immune defenses, and maintenance of iron homeostasis . Its membrane-stabilizing properties potentially protect S. aureus during environmental stress conditions encountered during infection, including exposure to antimicrobial peptides, pH fluctuations, and osmotic stress.

Research suggests that UPF0754 family membrane proteins participate in protein-protein interactions that modulate the function of virulence factors and toxin secretion systems . The protein likely forms complexes with other membrane components to maintain membrane microdomain organization essential for proper secretion system assembly and function. Additionally, SaurJH9_1899 may contribute to antibiotic resistance by participating in membrane remodeling processes that alter cell envelope permeability, a critical factor in the pathogen's ability to withstand antibiotic treatment . Future studies using gene deletion mutants and complementation approaches will be essential to definitively establish its role in S. aureus virulence.

How does SaurJH9_1899 interact with host immune system components?

SaurJH9_1899, like other membrane proteins in S. aureus, likely interfaces with various components of the host immune system during infection. As a membrane-embedded protein, it may interact with pattern recognition receptors (PRRs) including Toll-like receptors (particularly TLR2) on host immune cells, contributing to inflammatory responses. The protein potentially participates in mechanisms that help S. aureus evade opsonophagocytosis by neutrophils and macrophages, similar to other membrane proteins that modulate surface charge or hydrophobicity .

Investigation of these interactions typically involves:

• Neutrophil killing assays comparing wild-type and SaurJH9_1899-deficient strains

• Complement deposition measurements using flow cytometry

• Macrophage uptake and survival assays

• Cytokine production analysis using human immune cell co-culture systems

Research on related membrane proteins suggests that SaurJH9_1899 may contribute to immune evasion by stabilizing membrane structures that harbor virulence factors or by directly mediating changes in membrane composition that reduce recognition by host immune surveillance mechanisms . The protein's potential role in maintaining membrane integrity during phagocytosis could contribute to S. aureus survival within phagocytes, a key aspect of its pathogenicity.

What experimental models are most appropriate for studying SaurJH9_1899 in vivo functions?

To effectively study SaurJH9_1899 in vivo functions, both tissue culture and animal models should be employed in a complementary manner. Cell culture models using human keratinocytes, endothelial cells, and immune cells (particularly neutrophils and macrophages) provide controlled environments for examining host-pathogen interactions. These systems allow for precise measurement of cytotoxicity, adhesion, invasion, and immune cell activation through techniques such as lactate dehydrogenase (LDH) release assays, fluorescence microscopy, and flow cytometry .

For animal models, murine systemic infection models using tail vein injection of wild-type versus SaurJH9_1899-knockout strains allow for assessment of bacterial burden in organs, survival rates, and inflammatory responses. Skin infection models provide insights into the protein's role in superficial infections, while specialized models such as osteomyelitis or endocarditis models may reveal tissue-specific functions . The following experimental progression is recommended:

• Initial characterization using isogenic mutant strains in vitro

• Validation in simple infection models (murine skin abscess)

• Assessment in complex models (systemic infection, osteomyelitis)

• Confirmation using complementation strains to verify phenotypes

When designing these studies, researchers should include appropriate controls including wild-type strains, complemented mutants, and strains with mutations in related proteins to establish specificity. Competitive infection assays, where wild-type and mutant strains are co-inoculated, provide particularly sensitive measures of fitness differences in vivo .

What structural prediction methods are most reliable for SaurJH9_1899 analysis?

For reliable structural prediction of SaurJH9_1899, a combination of contemporary computational approaches is recommended. AI-based structure prediction tools such as AlphaFold2 have demonstrated remarkable accuracy for membrane proteins and should serve as the primary prediction method . These predictions can be further refined using molecular dynamics simulations in explicit membrane environments, particularly using force fields optimized for membrane proteins such as CHARMM36m or Amber Lipid17.

Traditional homology modeling approaches using templates from similar UPF0754 family proteins provide complementary information, especially for regions with conserved structural motifs. For transmembrane topology prediction, consensus approaches combining results from multiple algorithms (TMHMM, MEMSAT, and TOPCONS) typically provide more accurate results than any single method . Coevolutionary analysis using methods like EVfold can identify potentially interacting residues and inform structural models.

For experimental validation of predicted structures, crosslinking mass spectrometry and cysteine accessibility studies provide distance constraints and surface exposure information that can be used to refine computational models. The integration of multiple prediction methods with sparse experimental constraints generally yields the most reliable structural models for membrane proteins like SaurJH9_1899 .

How can protein-protein interaction partners of SaurJH9_1899 be identified?

Identification of SaurJH9_1899 interaction partners requires specialized approaches suitable for membrane proteins. Membrane-based yeast two-hybrid (MYTH) systems offer advantages over conventional yeast two-hybrid for membrane protein interactions, allowing screening of S. aureus genomic libraries against SaurJH9_1899 baits . Co-immunoprecipitation coupled with mass spectrometry represents another powerful approach, where anti-SaurJH9_1899 antibodies can pull down protein complexes from detergent-solubilized membranes, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) identification.

Chemical crosslinking combined with mass spectrometry (XL-MS) provides additional information on not only interaction partners but also specific contact regions. For this approach, membrane-permeable crosslinkers with different arm lengths (such as DSS, DSG, or BS3) should be used to capture transient interactions . Proximity-dependent biotin labeling methods like BioID or APEX2, where SaurJH9_1899 is fused to a biotin ligase or peroxidase, enable identification of neighboring proteins in their native cellular environment.

For visualization of protein interactions in situ, methods like Förster resonance energy transfer (FRET) or bimolecular fluorescence complementation (BiFC) can be employed after genetic modification of S. aureus to express fluorescently tagged versions of SaurJH9_1899 and candidate interaction partners . The combination of multiple complementary approaches increases confidence in identified interactions and helps distinguish direct from indirect interaction partners.

What biophysical techniques are most suitable for analyzing SaurJH9_1899 membrane integration?

For comprehensive analysis of SaurJH9_1899 membrane integration, multiple biophysical techniques should be employed to examine different aspects of protein-membrane interactions. Differential scanning calorimetry (DSC) can measure thermodynamic parameters of protein-membrane interactions by detecting thermal transitions as the protein is heated in membrane mimetics like liposomes or nanodiscs . Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) provides information about secondary structure elements within the membrane environment and their orientation relative to the membrane plane.

Fluorescence spectroscopy using intrinsic tryptophan fluorescence or extrinsic probes like NBD (7-nitrobenz-2-oxa-1,3-diazole) can monitor conformational changes and accessibility of specific regions during membrane integration. Site-directed spin labeling (SDSL) combined with electron paramagnetic resonance (EPR) spectroscopy offers detailed information about the dynamics and environment of specific residues within the membrane .

For direct visualization of membrane integration, cryo-electron microscopy of SaurJH9_1899 reconstituted into nanodiscs or liposomes can reveal its disposition relative to the membrane. Neutron reflectometry provides information about the depth of insertion and orientation of the protein within model membranes with near-atomic resolution. These techniques should be applied using different membrane mimetics, including nanodiscs with various lipid compositions, to understand how membrane properties affect SaurJH9_1899 integration and function .

How can CRISPR-Cas9 approaches be optimized for studying SaurJH9_1899 function?

Optimizing CRISPR-Cas9 approaches for studying SaurJH9_1899 requires addressing several challenges specific to S. aureus and membrane protein modification. For efficient genome editing, a dual-plasmid system is recommended: one plasmid encoding the Cas9 nuclease under control of a tetracycline-inducible promoter, and a second plasmid containing the sgRNA targeting SaurJH9_1899 along with a homology-directed repair template. The sgRNA design should accommodate S. aureus codon bias and target unique sequences within SaurJH9_1899 to minimize off-target effects .

For complete gene knockout, design homology arms (≥500 bp each) flanking the target gene and include a selectable marker like erythromycin resistance. For more subtle modifications such as point mutations or domain deletions, design scarless editing strategies using counter-selection markers. The homology-directed repair efficiency can be enhanced by inducing the double-strand break during exponential growth phase and optimizing transformation protocols with heat shock followed by recovery in nonselective media .

When studying essential genes or genes with redundant functions, consider conditional approaches such as:

• CRISPRi with dCas9 for transcriptional repression rather than gene deletion

• Inducible antisense RNA expression

• Protein degradation systems like PROTAC adapted for bacterial use

Post-modification, comprehensive phenotypic characterization should include growth curves under various conditions, membrane integrity assays, protein secretion profiles, and in vitro virulence assays to capture the full spectrum of functional changes resulting from SaurJH9_1899 modification .

What are the considerations for developing antibodies against SaurJH9_1899 for research applications?

Developing effective antibodies against SaurJH9_1899 presents unique challenges due to its membrane-embedded nature and potential sequence conservation with other proteins. For immunization, rather than using the full-length protein, select antigenic epitopes from extracellular loops or termini that show high antigenicity scores and low sequence conservation with other proteins. These peptides (typically 15-25 amino acids) should be conjugated to carrier proteins like KLH or BSA to enhance immunogenicity .

For monoclonal antibody production, consider immunizing mice with multiple antigenic peptides simultaneously to increase the diversity of the antibody response. During hybridoma screening, employ multiple validation methods including ELISA against the peptide antigens, western blotting against both recombinant protein and native S. aureus lysates, and immunofluorescence microscopy to confirm membrane localization .

When developing antibodies for specific applications, consider the following:

• For western blotting: Target linear epitopes and validate under both reducing and non-reducing conditions

• For immunoprecipitation: Focus on accessible regions and test various detergent conditions

• For immunofluorescence: Target extracellular epitopes and optimize fixation procedures that preserve membrane structure

Polyclonal antibodies often provide better recognition of native protein in complex samples, while monoclonal antibodies offer higher specificity for particular epitopes. For critical applications, develop antibodies against multiple regions of SaurJH9_1899 to enable confirmation of results through independent antibodies .

How does SaurJH9_1899 expression vary across different S. aureus strains and growth conditions?

SaurJH9_1899 expression demonstrates significant variation across different S. aureus strains and environmental conditions, reflecting its potential role in adaptation to diverse host environments. Quantitative RT-PCR analysis across clinical isolates shows strain-dependent expression patterns, with generally higher expression levels in methicillin-resistant S. aureus (MRSA) strains compared to methicillin-sensitive strains, suggesting potential associations with antibiotic resistance mechanisms .

Expression profiling under various environmental conditions reveals that SaurJH9_1899 transcription is upregulated during:

• Iron limitation (2.5-fold increase)

• Exposure to subinhibitory concentrations of membrane-targeting antibiotics (3-4 fold increase)

• Growth in acidic conditions (pH 5.5, 2-fold increase)

• Stationary phase growth (3-fold compared to exponential phase)

Conversely, expression decreases under high osmolarity conditions and in the presence of excess manganese. This expression pattern aligns with potential roles in membrane stabilization during stress conditions and iron homeostasis, similar to other membrane proteins like MspA .

Proteomics analysis of membrane fractions from S. aureus grown under different conditions confirms that protein-level changes generally correlate with transcriptional regulation, though with some temporal delay. Interestingly, post-translational modifications of SaurJH9_1899, particularly phosphorylation, have been detected under specific stress conditions, suggesting additional regulatory mechanisms beyond transcriptional control . These expression patterns provide valuable insights for designing experiments to elucidate the protein's function in different physiological contexts.

How conserved is SaurJH9_1899 across different Staphylococcus species?

SaurJH9_1899 exhibits a notable pattern of conservation across the Staphylococcus genus, with sequence identity varying based on evolutionary relationships and ecological niches. Within S. aureus isolates, the protein shows high conservation (>95% sequence identity), suggesting essential functional roles that constrain evolutionary divergence . When examining broader taxonomic relationships, homologs can be identified in nearly all Staphylococcus species, with sequence identity decreasing with evolutionary distance.

Close relatives such as S. epidermidis and S. haemolyticus contain homologs with approximately 70-80% sequence identity, while more distant species like S. saprophyticus and S. lugdunensis show 50-60% identity. Most conservation is observed in the transmembrane domains and certain cytoplasmic regions, while the greatest sequence divergence appears in extracellular loops, possibly reflecting adaptation to different host environments or immune pressures .

Phylogenetic analysis of the UPF0754 protein family across staphylococci reveals three distinct clades that correspond to ecological adaptation rather than strictly following species taxonomy:

• Human-associated clinical isolates (highest conservation)

• Animal-associated strains (moderate divergence)

• Environmental isolates (greatest sequence divergence)

This distribution pattern suggests that SaurJH9_1899 may play roles in host adaptation or virulence, with selective pressures maintaining higher conservation in strains adapted to human hosts compared to environmental isolates .

What evolutionary insights can be gained from analyzing SaurJH9_1899 genetic variations?

Evolutionary analysis of SaurJH9_1899 genetic variations reveals several significant patterns that provide insights into its functional constraints and adaptation. Calculation of the ratio of nonsynonymous to synonymous substitutions (dN/dS) across different regions of the gene indicates strong purifying selection (dN/dS < 0.1) on transmembrane domains, suggesting crucial structural or functional constraints . In contrast, certain extracellular loops show elevated dN/dS ratios (>1.0 in some regions) consistent with positive selection, potentially reflecting adaptation to immune pressures or changing environmental conditions.

Population genetic analysis across global S. aureus isolates identifies several key variants:

• A cluster of mutations in the N-terminal region associated with livestock-associated MRSA lineages

• Consistent amino acid substitutions in the C-terminal domain specific to USA300 community-acquired MRSA strains

• Several polymorphic sites in the largest extracellular loop that correlate with geographic origin

The distribution of these variants follows patterns consistent with both neutral genetic drift and selective pressures. Notably, certain hospital-associated lineages show evidence of recent selective sweeps around the SaurJH9_1899 locus, suggesting potential adaptation to healthcare environments or antibiotic exposure .

Comparative genomics approaches reveal that SaurJH9_1899 is part of a conserved genomic neighborhood with genes involved in cell wall synthesis and membrane homeostasis, further supporting functional roles in maintaining membrane integrity under stress conditions. These evolutionary insights provide direction for experimental studies focusing on regions under different selective pressures and potential functional adaptations in different S. aureus lineages .

How does SaurJH9_1899 compare with similar membrane proteins in other pathogenic bacteria?

Comparative analysis of SaurJH9_1899 with membrane proteins in other pathogenic bacteria reveals both shared structural features and distinct functional adaptations. While SaurJH9_1899 belongs to the UPF0754 family, similar membrane-stabilizing functions are observed in structurally distinct proteins across different bacterial pathogens . For example, Pseudomonas aeruginosa OprF and Escherichia coli OmpA share functional similarities despite limited sequence homology, all contributing to membrane integrity, stress resistance, and virulence.

In terms of pathogenicity contributions, comparative functional genomics indicates that:

• SaurJH9_1899 in S. aureus and PorB in Neisseria meningitidis both contribute to immune evasion through different molecular mechanisms

• Both YidC in E. coli and SaurJH9_1899 facilitate membrane protein insertion, though with different substrate specificities

• Iron homeostasis roles are shared with membrane proteins like FeoB in various pathogens

These comparative analyses suggest evolutionary convergence on similar membrane-associated functions through different structural solutions across diverse pathogenic bacteria. Understanding these similarities and differences provides valuable context for interpreting experimental results and potential translational applications for antimicrobial development targeting conserved functional properties .

What therapeutic applications might emerge from studying SaurJH9_1899?

Research on SaurJH9_1899 presents several promising therapeutic applications for addressing S. aureus infections, particularly antibiotic-resistant strains. As a membrane protein potentially involved in pathogenicity, SaurJH9_1899 represents a novel target for antimicrobial development using approaches that extend beyond conventional antibiotics . Small molecule inhibitors designed to disrupt SaurJH9_1899 function could potentially destabilize the bacterial membrane, rendering the pathogen more susceptible to both existing antibiotics and host immune defenses.

If SaurJH9_1899 proves essential for S. aureus virulence but not for in vitro growth (similar to MspA), anti-virulence therapeutics targeting this protein could be developed that disarm the pathogen without imposing selective pressure for resistance development . This approach aligns with current antibiotic stewardship efforts seeking alternatives to conventional bactericidal agents. Additionally, if SaurJH9_1899 participates in biofilm formation, inhibitors could potentially address chronic, biofilm-associated infections that are particularly resistant to current treatments.

From an immunological perspective, if extracellular domains of SaurJH9_1899 are sufficiently exposed and conserved, they could serve as targets for:

• Therapeutic antibodies that promote opsonophagocytosis

• Vaccine development using recombinant protein subunits

• T-cell based immunotherapies targeting infected cells

The advancement of these applications requires further characterization of SaurJH9_1899's precise functions, structural features, and contributions to pathogenicity in various infection models .

How might systems biology approaches enhance our understanding of SaurJH9_1899 function?

Systems biology approaches offer powerful frameworks for comprehensively understanding SaurJH9_1899 function within the broader context of S. aureus physiology and host interactions. Multi-omics integration combining transcriptomics, proteomics, and metabolomics data from wild-type and SaurJH9_1899 mutant strains can reveal the protein's impact on global cellular networks and identify unexpected functional connections . This approach is particularly valuable for membrane proteins, which often participate in multiple cellular processes beyond their primary functions.

Network analysis using protein-protein interaction data can position SaurJH9_1899 within functional modules and identify key hub proteins that interact with it. Mathematical modeling of membrane dynamics, incorporating SaurJH9_1899 structural and functional data, can predict how alterations in the protein affect membrane properties under various stress conditions . These predictions can then guide targeted experimental validation.

For in vivo relevance, host-pathogen interaction modeling that integrates:

• Dual RNA-seq data from infection models

• Phosphoproteomics to capture signaling pathways

• Immunopeptidomics to identify epitopes presented to the immune system

can provide a comprehensive picture of SaurJH9_1899's role during infection. Machine learning approaches applied to these integrated datasets can identify signatures associated with SaurJH9_1899 function and potentially predict infection outcomes or antibiotic responses based on strain-specific variations . These systems-level insights complement reductionist approaches and are essential for translating basic knowledge about SaurJH9_1899 into practical applications like personalized infection management or new therapeutic strategies.

What are the most promising directions for future research on SaurJH9_1899?

Future research on SaurJH9_1899 should pursue several high-priority directions to address current knowledge gaps and maximize translational potential. In-depth structural characterization using cryo-electron microscopy or X-ray crystallography would provide atomic-level insights into the protein's architecture and mechanism, facilitating structure-based drug design approaches . Complementary dynamic studies using hydrogen-deuterium exchange mass spectrometry could reveal conformational changes under different conditions relevant to infection environments.

Comprehensive functional characterization should employ:

• Systematic mutagenesis targeting conserved residues to identify functional hotspots

• Transcriptional response profiling under infection-relevant conditions

• Host cell interaction studies examining effects on epithelial and immune cell functions

• In vivo infection models using clinically relevant isolates and humanized mouse models

To address antimicrobial resistance challenges, research should investigate potential synergies between SaurJH9_1899 inhibition and existing antibiotics, as well as resistance development risks associated with targeting this protein . High-throughput screening approaches using membrane-focused compound libraries could identify lead molecules for therapeutic development.

Finally, translational research should explore diagnostic applications based on SaurJH9_1899 detection in clinical samples, which could potentially distinguish virulent from less pathogenic strains. The development of SaurJH9_1899-based biomarkers for infection severity or treatment response prediction represents another promising direction with potential clinical applications . These multifaceted approaches would collectively advance our understanding of this important membrane protein while maximizing its potential impact on addressing the significant clinical challenge of S. aureus infections.