OST4B Antibody

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Description

Molecular Characterization of OST4B

OST4B (encoded by At3g12587 in Arabidopsis) is a paralog of OST4A and shares structural homology with yeast Ost4p. Key features include:

  • Size: ~4 kDa, with a single transmembrane domain .

  • Function: Stabilizes interactions between OST subunits (e.g., STT3A, ribophorin I) and ensures efficient N-glycosylation of substrate proteins .

  • Localization: Integral membrane protein of the ER .

Role in N-Glycosylation

OST4B forms part of the STT3A-containing OST complex in plants. Studies using Arabidopsis mutants reveal:

  • Complex Stability: OST4B depletion destabilizes OST complexes, leading to underglycosylation of glycoproteins like CBP65 and GFP-KOR1 .

  • Substrate Specificity: OST4B influences glycosylation efficiency for substrates requiring the STT3A isoform .

Interaction Partners

ProteinInteraction TypeMethod UsedReference
STT3ACo-purificationTAP-MS, BN-PAGE
Ribophorin ICo-immunoprecipitationIP with OST4B-mRFP
DAD1/DAD2Genetic epistasisMutant complementation

Antibody Availability

Antibody NameHostReactivityApplicationsVendor
OST4 Antibody (C-terminal)RabbitHuman, Mouse, DogWBMyBioSource
Anti-S. cerevisiae OST4RabbitYeastWB, ELISAMyBioSource
Anti-S. pombe OST4RabbitFission yeastWB, ELISAMyBioSource

Notes:

  • These antibodies may cross-react with OST4B in plants due to sequence conservation in transmembrane regions .

  • Researchers often use epitope-tagged OST4B (e.g., OST4B-mRFP) with anti-RFP antibodies for detection .

Functional Implications

OST4B deficiency in Arabidopsis results in:

  • Abiotic Stress Sensitivity: Impaired cellulose biosynthesis and ER stress responses .

  • Immune Defects: Reduced glycosylation of pattern recognition receptors like EFR, compromising pathogen defense .

Future Directions

  • Develop species-specific OST4B antibodies to study its role in plant-specific glycosylation pathways.

  • Explore OST4B’s regulatory role in abiotic stress adaptation and immune signaling .

Product Specs

Buffer
**Preservative:** 0.03% Proclin 300
**Constituents:** 50% Glycerol, 0.01M PBS, pH 7.4
Form
Liquid
Lead Time
Made-to-order (14-16 weeks)
Synonyms
OST4B antibody; Os03g0392050 antibody; Dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit 4B antibody
Target Names
OST4B
Uniprot No.

Target Background

Function
OST4B Antibody targets a subunit of the oligosaccharyl transferase (OST) complex. This complex catalyzes the initial transfer of a defined glycan (Glc(3)Man(9)GlcNAc(2) in eukaryotes) from the lipid carrier dolichol-pyrophosphate to an asparagine residue within an Asn-X-Ser/Thr consensus motif in nascent polypeptide chains. This is the first step in protein N-glycosylation. N-glycosylation occurs cotranslationally, and the OST complex associates with the Sec61 complex at the channel-forming translocon complex that mediates protein translocation across the endoplasmic reticulum (ER). All subunits are required for maximal enzyme activity.
Database Links

KEGG: osa:9267004

STRING: 39947.LOC_Os03g27424.1

UniGene: Os.9737

Protein Families
OST4 family
Subcellular Location
Endoplasmic reticulum membrane; Single-pass type III membrane protein.

Q&A

What controls should I include when using OST4B antibody for immunocytochemistry?

When working with OST4B antibody or any antibody for immunocytochemistry, three essential control types must be included: primary antibody controls, secondary antibody controls, and labeling controls. For primary antibody controls, four approaches are recommended:

  • Genetic approach: The most rigorous control involves manipulating the expression of the target protein through knockout or knockdown experiments. This confirms specificity by showing antibody binding is lost when the target protein is absent .

  • Multiple antibodies to the same target: Using different antibodies that recognize distinct epitopes of your target protein. If they show identical labeling patterns, this increases confidence in specificity .

  • Absorbed antibody controls: Mix the primary antibody with purified antigen before tissue application. The antibody's function is lost when it binds the antigen prior to incubation, so staining should disappear if the antibody is specific. This requires properly purified antigen, not crude homogenates .

  • Secondary antibody controls: Process samples with omission of the primary antibody while including all secondary antibodies. This control detects non-specific binding of secondary antibodies and is particularly important when using multiple primary antibodies in a single experiment .

How can I efficiently search for antibodies with similar properties to OST4B?

The Observed Antibody Space (OAS) database provides a valuable resource for researchers looking to compare antibody sequences and properties. The updated OAS contains 1.5 billion unpaired sequences from 80 studies and paired sequencing data from five studies, making it an excellent reference point.

To search effectively:

  • Use the new OAS web server (http://opig.stats.ox.ac.uk/webapps/oas/) which offers standardized search parameters .

  • Utilize the sequence-based search option to find antibodies with the same V and J genes as your query sequence .

  • Take advantage of the database's MiAIRR compliance, which includes both nucleotide and amino acid sequences for each entry .

  • Review the additional sequence annotations provided, such as junction sequences and comments on potential structural issues (e.g., lack of conserved cysteines or unusual insertions) .

This approach allows for rapid identification of antibodies with structural or functional similarities to your antibody of interest, potentially revealing important insights about binding properties or cross-reactivity.

What information should I document when reporting OST4B antibody use in publications?

To ensure reproducibility and transparency in antibody-based research, comprehensive documentation is essential. Based on current standards in the field, researchers should document:

  • Complete sequence information (if available), including both amino acid and nucleotide sequences

  • Source of the antibody (commercial vendor or in-house production details)

  • Catalog number and lot number (for commercial antibodies)

  • Validated applications and concentrations/dilutions used

  • Detailed validation data demonstrating specificity

  • All controls used in the experiment (primary, secondary, and labeling)

  • Isotype and clonality (monoclonal vs polyclonal)

  • Complete experimental conditions (fixation method, blocking reagents, incubation times/temperatures)

This documentation aligns with MiAIRR (Minimal Information about Adaptive Immune Receptor Repertoire) compliance standards, which have been implemented in databases like OAS to make antibody data more findable, accessible, interoperable, and reusable (FAIR) .

How can computational models predict OST4B antibody binding specificity and cross-reactivity?

Computational modeling of antibody specificity has advanced significantly in recent years. Current approaches combine biophysics-informed modeling with extensive selection experiments to predict binding profiles:

  • Energy function optimization: Advanced models employ energy functions associated with binding modes to predict specificity. For designing antibodies with custom binding profiles, optimization algorithms can minimize energy functions for desired ligands while maximizing them for undesired ligands .

  • Phage display data integration: Models built on phage-display experiments can provide training and test sets for computational predictions. These models can identify antibody sequences with either cross-specific properties (interaction with several distinct ligands) or highly specific properties (interaction with a single ligand while excluding others) .

  • CDR3 variation analysis: Since complementarity-determining region 3 (CDR3) often determines binding specificity, models that systematically analyze variations in this region (e.g., examining combinations of amino acids in four consecutive positions) can predict specificity changes .

The integration of these computational approaches with experimental validation creates a powerful toolset for designing antibodies with desired physical properties. This methodology is particularly valuable when engineering antibodies for research applications requiring discrimination between very similar ligands .

What approaches can modify OST4B antibody specificity for targeting closely related antigens?

Modifying antibody specificity for targeting closely related antigens involves several sophisticated approaches:

  • CDR engineering: Systematic variation of the complementarity-determining regions, particularly CDR3, can generate antibodies with customized specificity profiles. This approach relies on understanding which amino acid combinations in key positions determine binding preferences .

  • Joint optimization for cross-specificity: To create antibodies that can bind to multiple related antigens, joint minimization of energy functions associated with desired ligands can be employed. This computational approach identifies sequences likely to recognize multiple targets .

  • Negative selection optimization: Conversely, to create highly specific antibodies that discriminate between similar antigens, optimization algorithms can minimize binding energy for the desired target while maximizing it for undesired targets, effectively engineering exclusivity into the binding profile .

  • Experimental validation through phage display: Following computational prediction, candidate sequences can be tested through phage display experiments where antibodies are selected against various combinations of ligands. This provides empirical validation of the predicted specificity profiles .

These approaches combine computational prediction with experimental validation to develop antibodies with precisely engineered binding properties, allowing researchers to create reagents tailored to specific experimental needs.

How does the non-toxic antibody-based conditioning approach compare to traditional methods for stem cell transplantation?

Recent research has shown promising advances in antibody-based conditioning for stem cell transplantation that could potentially revolutionize treatment approaches:

  • Targeted elimination of stem cells: CD117-targeting antibodies (such as SR1) can selectively eliminate blood-forming stem cells in bone marrow without the toxic effects of traditional chemotherapy or radiation. This antibody binds to CD117 protein on hematopoietic stem cells, preventing its function and effectively preparing the bone marrow for transplantation .

  • Reduced toxicity profile: Traditional pre-transplant conditioning regimens involving chemotherapy and radiation are highly toxic, limiting which patients can undergo the procedure. The antibody-based approach offers a gentler alternative that could expand treatment eligibility to many more patients with blood and immune disorders .

  • Potential applications: This less toxic approach could potentially cure conditions including sickle cell disease, thalassemia, autoimmune disorders, and other blood disorders that currently may not be treated with stem cell transplantation due to the risks of conventional conditioning .

  • Scientific basis: The efficacy of this approach has been demonstrated in both mice and non-human primates, where antibodies targeting CD117 safely and efficiently eliminated blood-forming stem cells, preparing the bone marrow for successful transplantation of healthy donor cells .

This antibody-based conditioning approach represents a significant advancement that could dramatically expand the therapeutic applications of stem cell transplantation by reducing associated risks and making the procedure accessible to a broader patient population.

What factors should I consider when designing specificity tests for OST4B antibody?

Designing rigorous specificity tests for antibodies requires careful consideration of several critical factors:

  • Multiple validation approaches: Implement at least two independent methods to validate specificity. Options include:

    • Genetic controls (knockout/knockdown of target)

    • Western blotting compared to immunocytochemistry

    • Multiple antibodies to different epitopes

    • Absorption controls with purified antigen

  • Control selection: When using multiple primary antibodies in a single experiment, design controls where each primary antibody is omitted sequentially while including all secondary antibodies. This identifies any cross-reactivity issues between antibodies or incorrect binding of secondary antibodies .

  • Quantitative analysis: Establish quantitative criteria for determining specificity, such as signal-to-noise ratios or comparison to background staining levels in negative controls.

  • Cross-reactivity assessment: Test against related proteins, particularly those with similar epitopes or structural homology to your target protein.

  • Documentation: Record complete experimental conditions including buffer compositions, incubation times/temperatures, and washing protocols to ensure reproducibility.

How can I optimize OST4B antibody use in multiplexed immunoassays?

Optimizing antibody performance in multiplexed immunoassays requires systematic protocol development:

  • Antibody compatibility assessment:

    • Test each antibody individually before combining

    • Verify that secondary antibodies do not cross-react with inappropriate primary antibodies

    • Process samples with omission of each primary antibody but inclusion of all secondary antibodies to detect cross-reactivity

  • Titration optimization:

    • Perform dilution series to identify optimal concentration for each antibody

    • Balance signal strength against background/non-specific binding

    • Consider that optimal concentrations may differ in multiplexed format compared to single-antibody applications

  • Order of application:

    • Test different sequences of antibody application

    • Consider sequential rather than simultaneous application if cross-reactivity occurs

    • Implement blocking steps between different antibody applications if needed

  • Signal separation strategies:

    • Carefully select fluorophores with minimal spectral overlap

    • Include single-color controls to establish compensation parameters

    • Use antibodies from different host species when possible to facilitate discrimination

  • Validation with known samples:

    • Include positive and negative control samples with known expression patterns

    • Compare multiplexed results with single-antibody staining patterns

    • Verify that colocalization signals represent true biological overlap rather than technical artifacts

Following these methodological approaches will help ensure reliable and interpretable results from multiplexed immunoassays using OST4B antibody in combination with other detection reagents.

What database resources can inform experimental design for antibody-based research?

Several specialized databases provide valuable resources for antibody-based research design:

  • Observed Antibody Space (OAS):

    • Contains 1.5 billion unpaired sequences from 80 studies

    • Includes paired sequencing data from five studies

    • Provides both nucleotide and amino acid sequences

    • Offers standardized search parameters and sequence-based search options

    • Contains SARS-CoV-2 data and antibodies from diverse sources

  • Related antibody databases:

    • ImmuneAccess: Large set of annotated CDR3 sequences

    • PIRD (pan immune repertoire database): Collection of BCR-seq data

    • RAPID (rep-seq dataset analysis platform): Identically processed human antibodies

    • AIRR Data Commons (ADC): Network of geographically distributed AIRR-compliant repositories accessible through a single API

  • Database functionalities:

    • Search for antibodies with similar V and J genes

    • Review sequence annotations including junction sequences

    • Identify potential structural issues (e.g., unusual insertions or deletions)

    • Access MiAIRR-compliant data for improved interoperability

    • Download data for further computational analysis

Using these resources can inform experimental design by:

  • Identifying similar antibodies with established properties

  • Understanding natural sequence diversity in the targeted epitope region

  • Selecting appropriate controls based on similar antibody characteristics

  • Generating hypotheses about binding properties based on sequence similarities

  • Designing validation experiments informed by existing data

These databases represent significant advances in making antibody data more FAIR (findable, accessible, interoperable, and reusable), though researchers should be aware that different processing pipelines between databases may present challenges for direct comparisons .

How should I approach contradictory results when validating OST4B antibody specificity?

When faced with contradictory results during antibody validation, a systematic troubleshooting approach is essential:

  • Methodological assessment:

    • Compare experimental conditions between contradictory results

    • Evaluate differences in sample preparation, fixation methods, or detection systems

    • Consider that antibody performance may vary across applications (ICC vs. WB vs. ELISA)

  • Control evaluation:

    • Review all controls, especially primary antibody controls

    • Implement genetic approaches (knockout/knockdown) as the gold standard

    • Use multiple antibodies to the same target to verify labeling patterns

    • Perform absorption controls with purified antigen

  • Technical variables investigation:

    • Test different lots of the antibody for consistency

    • Evaluate the impact of antigen retrieval methods

    • Consider tissue/cell-specific differences in epitope accessibility

    • Assess potential post-translational modifications affecting recognition

  • Quantitative analysis:

    • Establish signal-to-noise thresholds for positive results

    • Perform dose-response curves to identify optimal concentrations

    • Use statistical methods to evaluate significance of contradictory findings

  • Resolution strategies:

    • Generate consensus results through multiple validation methods

    • Consider that both results may be correct under different conditions

    • Consult with antibody suppliers or other labs using the same antibody

    • Document all contradictory findings transparently in publications

What statistical approaches are most appropriate for analyzing antibody binding data?

Analyzing antibody binding data requires appropriate statistical methods to ensure valid interpretations:

  • Descriptive statistics:

    • Measures of central tendency (mean, median) and dispersion (standard deviation, IQR)

    • Normalization methods to account for background and non-specific binding

    • Visualization techniques (scatter plots, box plots, heat maps) to identify patterns

  • Comparative analyses:

    • Paired vs. unpaired t-tests for comparing binding between conditions

    • ANOVA with post-hoc tests for multiple condition comparisons

    • Non-parametric alternatives (Mann-Whitney, Kruskal-Wallis) for non-normally distributed data

    • Correction for multiple comparisons (Bonferroni, Benjamini-Hochberg) to control error rates

  • Correlation and regression:

    • Pearson or Spearman correlation for assessing relationships between variables

    • Linear or non-linear regression to model binding kinetics

    • Multivariate analyses to account for confounding factors

  • Binding kinetics analysis:

    • Calculation of KD, kon, and koff rates

    • Scatchard plots or non-linear regression for affinity determination

    • Models accounting for avidity effects in multivalent binding

  • Advanced computational approaches:

    • Machine learning algorithms to identify binding patterns

    • Energy function optimization techniques for predicting binding specificity

    • Statistical models incorporating structural information

How can I integrate OST4B antibody data with other -omics datasets for comprehensive analysis?

Integrating antibody data with other -omics datasets provides a more comprehensive understanding of biological systems:

  • Multi-omics data integration approaches:

    • Correlation analysis between antibody binding patterns and transcriptomic data

    • Network analysis to identify functional relationships between proteins detected by antibodies and other molecular features

    • Dimensionality reduction techniques (PCA, t-SNE) to visualize relationships across datasets

    • Clustering methods to identify patterns across multiple data types

  • Database integration strategies:

    • Utilize standardized formats like MiAIRR compliance to facilitate data interoperability

    • Link antibody sequences in OAS with functional data from other databases

    • Implement unique identifiers to track relationships between datasets

  • Computational modeling:

    • Develop biophysics-informed models that incorporate structural data with binding information

    • Use machine learning approaches trained on multiple data types

    • Implement validation strategies that cross-reference predictions across datasets

  • Visualization tools:

    • Create integrated dashboards showing relationships between datasets

    • Develop network visualizations highlighting connections between antibody targets and other molecular features

    • Implement interactive tools allowing exploration of complex multi-omics relationships

  • Validation strategies:

    • Design experiments that test predictions from integrated analyses

    • Implement orthogonal methods to verify key findings

    • Establish quantitative metrics for assessing concordance between datasets

These approaches enable researchers to contextualize antibody binding data within the broader molecular landscape, leading to more holistic understanding of biological systems and potentially identifying novel relationships between molecular features.

How can I address inconsistent staining patterns when using OST4B antibody?

Inconsistent staining patterns are a common challenge in antibody-based experiments. A systematic troubleshooting approach includes:

  • Sample preparation assessment:

    • Evaluate fixation methods and duration

    • Standardize antigen retrieval protocols

    • Control for tissue/cell processing variables

    • Ensure consistent handling of all samples

  • Antibody validation:

    • Verify antibody specificity using multiple approaches

    • Test different antibody lots for consistency

    • Perform titration experiments to identify optimal concentration

    • Consider storage conditions and freeze-thaw cycles

  • Protocol optimization:

    • Standardize incubation times and temperatures

    • Optimize blocking conditions to reduce non-specific binding

    • Evaluate buffer composition effects

    • Ensure adequate washing between steps

  • Controls implementation:

    • Include positive and negative tissue controls

    • Perform secondary antibody-only controls

    • Use absorption controls with purified antigen

    • Consider genetic controls (knockout/knockdown)

  • Technical variations:

    • Minimize day-to-day procedural differences

    • Control for operator variability

    • Standardize image acquisition settings

    • Implement quantitative analysis methods

By systematically addressing these factors, researchers can identify the source of inconsistency and establish reliable, reproducible staining protocols for their antibody-based experiments.

What approaches can resolve cross-reactivity issues with OST4B antibody?

Resolving cross-reactivity issues requires a combination of analytical and experimental approaches:

  • Cross-reactivity characterization:

    • Identify the cross-reacting molecules through mass spectrometry or immunoprecipitation

    • Compare sequences/structures of intended target versus cross-reacting molecules

    • Determine if cross-reactivity is due to epitope similarity or non-specific binding

  • Experimental modifications:

    • Optimize blocking conditions (test different blocking agents, concentrations, and times)

    • Adjust antibody concentration through careful titration experiments

    • Modify buffer conditions (salt concentration, detergents, pH)

    • Implement more stringent washing protocols

  • Alternative antibody selection:

    • Test antibodies targeting different epitopes of the same protein

    • Use antibodies from different host species or production methods

    • Consider monoclonal alternatives if using polyclonal antibodies

  • Absorption strategies:

    • Pre-absorb the antibody with purified cross-reacting proteins

    • Implement competitive binding approaches to block cross-reactive epitopes

    • Use specific peptides to absorb antibodies recognizing unwanted epitopes

  • Computational prediction:

    • Employ biophysics-informed modeling to predict cross-reactivity

    • Design modified antibodies with enhanced specificity

    • Use energy function optimization to minimize binding to undesired targets

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