Recombinant Helianthus annuus Putative ATP synthase protein YMF19 (YMF19)

What is Helianthus annuus YMF19 and what is its primary function?

Helianthus annuus YMF19 (UniProt: P41248) is a putative ATP synthase protein found in common sunflower. It functions as part of the cellular machinery responsible for ATP synthesis through the conversion of electrochemical energy into chemical energy stored in ATP molecules . The protein is classified under EC number 3.6.3.14, indicating its role as an ATP synthase.

As a putative ATP synthase component, YMF19 likely participates in the membrane-bound enzyme complex that catalyzes the final step of oxidative phosphorylation, contributing to energy production in plant cells. The "putative" designation indicates that while its sequence and structure suggest this function, further experimental validation may be required to confirm its precise role in sunflower energy metabolism .

How does Helianthus annuus YMF19 compare to homologous proteins in other plant species?

Helianthus annuus YMF19 shares significant sequence homology with putative ATP synthase proteins in other plant species, particularly those in Marchantia polymorpha (liverwort) and Oenothera berteroana (evening primrose) . A comparative analysis reveals:

*Estimated from available data

The conservation of this protein across evolutionarily divergent plant species (spanning from liverworts to flowering plants) suggests its fundamental importance in plant energy metabolism . The differences in protein length and specific amino acid composition likely reflect adaptations to specific ecological niches and metabolic requirements of each species.

Functional motifs related to ATP binding and catalysis appear to be highly conserved, while peripheral regions show greater variability, suggesting that the core catalytic function has been maintained throughout plant evolution while allowing for species-specific adaptations in regulatory or structural regions .

How is the YMF19 gene positioned within the sunflower genome and what implications does this have for its evolution?

The YMF19 gene exists within the complex sunflower genome, which is notably composed of over 81% transposable elements, with 77% being long terminal repeat (LTR) retrotransposons . This genomic context has significant implications for YMF19's evolution and function.

The sunflower genome is large (~3.5 Gb) and has been shaped by extensive transposon activity, particularly by chromodomain-containing Gypsy LTR retrotransposons, which are disproportionately represented in gene-containing regions . This genomic architecture likely influences YMF19's:

• Expression regulation - Nearby transposable elements may affect promoter activity and expression patterns

• Evolutionary history - The high rate of LTR retrotransposon insertions in the sunflower genome suggests that YMF19's genomic neighborhood has likely changed significantly since the origin of the species

• Potential for variation - The dynamic nature of the sunflower genome, with its high transposon content, may contribute to variation in YMF19 across populations

Research indicates that biased homologous recombination efficacy in removing LTR retrotransposon DNA has shaped the chromatin and DNA landscape surrounding genes like YMF19 . This genomic context must be considered when studying YMF19's evolution, as it provides insight into how selection has maintained this gene's function amid extensive genomic restructuring driven by transposable element activity.

What role might YMF19 play in sunflower adaptation to environmental stressors?

YMF19, as a putative ATP synthase protein involved in energy metabolism, may play a critical role in sunflower adaptation to environmental stressors, particularly those affecting energy homeostasis. Recent research on sunflower adaptation provides insight into how YMF19 might contribute to stress responses:

Studies on repeatability of adaptation in Helianthus species have identified genomic regions associated with local adaptation to environmental variables such as frost-free days (NFFD) . While YMF19 hasn't been specifically identified in these studies, proteins involved in energy metabolism are often implicated in stress responses.

The putative functions of YMF19 suggest several potential mechanisms of involvement in stress adaptation:

• Cold stress response - ATP synthase activity often changes under temperature stress, and related genes like COLD-RESPONSIVE PROTEIN KINASE 1 (CRPK1) have been identified in regions associated with adaptation to frost-free days in sunflowers

• Drought tolerance - Energy metabolism reconfiguration is a key response to water limitation, potentially involving modifications to ATP synthase activity

• Metabolic adjustments - YMF19 may participate in the metabolic adjustments necessary for adaptation to various environmental conditions

Environmental stress often imposes energetic constraints on plants, requiring altered ATP production and utilization. As a component of ATP synthesis machinery, YMF19 might be subject to selection pressures in populations adapting to different environments, potentially resulting in functional variants that optimize energy production under specific conditions .

What are the most effective methods for expressing and purifying recombinant Helianthus annuus YMF19 for functional studies?

Effective expression and purification of recombinant Helianthus annuus YMF19 requires careful consideration of protein characteristics and experimental goals. Based on current approaches with this and similar proteins, the following methodology is recommended:

Expression System Selection:

The most common and effective expression system for recombinant YMF19 is Escherichia coli, which allows for high-yield production . The BL21(DE3) strain is particularly suitable as it lacks key proteases that might degrade the recombinant protein.

Expression Vector Design:

• Incorporate a His-tag (typically 6×His) at either the N- or C-terminus to facilitate purification

• Include a cleavable tag if native protein is required for downstream applications

• Optimize codon usage for E. coli expression

• Consider using a vector with a T7 promoter for inducible expression

Expression Protocol:

• Transform the expression construct into E. coli BL21(DE3)

• Culture in LB medium to OD600 of 0.6-0.8

• Induce expression with IPTG (0.1-1.0 mM)

• Reduce temperature to 18-25°C after induction to enhance proper folding

• Continue expression for 16-20 hours

Purification Strategy:

• Cell lysis using sonication or pressure-based methods in a buffer containing:

  • 50 mM Tris-HCl, pH 8.0

  • 300 mM NaCl

  • 10% glycerol

  • 1 mM PMSF and appropriate protease inhibitors

• Immobilized Metal Affinity Chromatography (IMAC) using Ni-NTA resin

• Size exclusion chromatography for further purification

• Storage in Tris-based buffer with 50% glycerol at -20°C or -80°C to maintain stability

This approach typically yields 1-5 mg of purified protein per liter of bacterial culture, sufficient for most functional and structural studies.

What experimental approaches are most suitable for characterizing the enzymatic activity of YMF19?

Characterizing the enzymatic activity of YMF19 as a putative ATP synthase requires specialized approaches that account for its membrane-associated nature and specific catalytic properties. The following methodological approaches are recommended:

Reconstitution into Liposomes:

• Prepare liposomes from plant phospholipids (phosphatidylcholine and phosphatidylethanolamine)

• Incorporate purified YMF19 using detergent-mediated reconstitution

• Remove detergent via dialysis or adsorption to Bio-Beads

ATP Synthase Activity Assay:

• Create a proton gradient across the liposome membrane using acid-base transition or ionophores

• Measure ATP synthesis by:

  • Luciferin-luciferase assay for real-time ATP detection

  • 32P-labeled ADP incorporation into ATP

  • HPLC analysis of reaction products

ATP Hydrolysis Assay (Reverse Reaction):

• Measure inorganic phosphate release using:

  • Malachite green colorimetric assay

  • EnzChek Phosphate Assay Kit

• Determine enzyme kinetics parameters (Km, Vmax, kcat)

Proton Translocation Measurement:

• Monitor pH changes using pH-sensitive fluorescent dyes (ACMA or pyranine)

• Use a stopped-flow apparatus for rapid kinetic measurements

Inhibitor Studies:

• Test sensitivity to known ATP synthase inhibitors (oligomycin, DCCD, venturicidin)

• Determine IC50 values and inhibition mechanisms

For comprehensive characterization, combine these approaches with structural studies such as circular dichroism spectroscopy to assess secondary structure elements and thermal stability . These methods collectively provide a detailed functional profile of YMF19's ATP synthase activity.

What approaches can be used to study the interaction of YMF19 with other components of the ATP synthase complex?

Studying the interactions of YMF19 with other components of the ATP synthase complex requires methods that can detect and characterize protein-protein interactions, particularly in the context of membrane-associated complexes. The following approaches are recommended:

Co-immunoprecipitation (Co-IP):

• Generate specific antibodies against YMF19 or use anti-tag antibodies for recombinant versions

• Solubilize membrane fractions using mild detergents (digitonin, DDM, or Triton X-100)

• Perform immunoprecipitation followed by mass spectrometry to identify interacting partners

• Validate key interactions using reverse Co-IP with antibodies against identified partners

Crosslinking Mass Spectrometry (XL-MS):

• Treat intact membranes or purified complexes with crosslinking agents (DSS, BS3, or formaldehyde)

• Digest crosslinked samples and analyze by LC-MS/MS

• Identify crosslinked peptides using specialized software (pLink, xQuest)

• Map interaction interfaces based on crosslinked residues

Blue Native PAGE:

• Solubilize membrane complexes under non-denaturing conditions

• Separate intact complexes on gradient blue native gels

• Identify complex components by:

  • Western blotting with specific antibodies

  • Excising bands for MS analysis

  • Second-dimension SDS-PAGE

Förster Resonance Energy Transfer (FRET):

• Generate fluorescent protein fusions of YMF19 and putative interaction partners

• Express in appropriate cell systems or reconstitute in vitro

• Measure FRET signals to detect proximity-based interactions

• Perform acceptor photobleaching or lifetime measurements for quantitative analysis

Surface Plasmon Resonance (SPR):

• Immobilize purified YMF19 on a sensor chip

• Flow potential interaction partners over the surface

• Measure binding kinetics and affinity constants

• Validate key interactions with reverse orientation experiments

These methodologies can be complemented by structural approaches such as cryo-electron microscopy of the intact ATP synthase complex to position YMF19 within the larger assembly and understand its functional contributions in the context of the complete enzyme .

How can evolutionary genomics approaches be applied to understand the function and conservation of YMF19 across plant species?

Evolutionary genomics approaches provide powerful tools for understanding YMF19's function and conservation across plant species, offering insights that direct experimental approaches might miss. The following methodological framework is recommended:

Comparative Sequence Analysis:

• Collect YMF19 homologs from diverse plant species spanning major evolutionary lineages

• Perform multiple sequence alignment using MUSCLE or MAFFT algorithms

• Calculate sequence conservation scores to identify functionally critical residues

• Map conservation onto predicted structural models to identify functional domains

Selection Pressure Analysis:

• Calculate dN/dS ratios (ratio of non-synonymous to synonymous substitution rates) using PAML or HyPhy

• Identify sites under positive selection, which may indicate adaptive evolution

• Detect signatures of purifying selection, suggesting functional constraints

• Correlate selection patterns with structural and functional domains

Synteny and Genomic Context Analysis:

Given the complex genome of Helianthus annuus with its high transposable element content (>81%) , analyzing synteny can reveal:

• Conservation of gene order and genomic context across species

• Transposition events that may have affected YMF19 regulation

• Co-evolved gene clusters that may function together with YMF19

Phylogenetic Profiling:

• Generate a presence/absence matrix of YMF19 across species

• Correlate this profile with other genes to identify functionally related proteins

• Identify convergent evolution patterns that may indicate functional importance

Expression Pattern Evolution:

• Compare expression profiles of YMF19 homologs across species

• Identify conserved and divergent expression patterns

• Correlate expression changes with adaptive traits or environmental responses

The sunflower genome's unique evolutionary history, shaped by extensive transposable element activity , provides a valuable context for understanding how YMF19 has evolved within this dynamic genomic landscape. Regions showing repeatable patterns of association across multiple sunflower species may indicate functionally important loci under similar selection pressures .

What computational methods can be used to predict the structure and function of YMF19 in the absence of experimental structural data?

In the absence of experimental structural data for YMF19, several computational methods can be employed to predict its structure and function, providing valuable insights for experimental design and functional hypothesis generation:

Homology Modeling:

• Identify suitable templates from structurally characterized ATP synthase components using programs like BLAST against the PDB database

• Generate homology models using platforms such as SWISS-MODEL, Phyre2, or MODELLER

• Refine models using molecular dynamics simulations to optimize geometry and remove steric clashes

• Validate models using PROCHECK, VERIFY3D, or MolProbity to assess stereochemical quality

Ab Initio Structure Prediction:

For regions lacking homologous templates:

• Use Rosetta, I-TASSER, or AlphaFold2 for de novo structure prediction

• Generate multiple models and cluster them to identify recurring structural motifs

• Assess model confidence using scoring functions specific to each method

Transmembrane Topology Prediction:

Given YMF19's likely membrane association:

• Predict transmembrane regions using TMHMM, MEMSAT, or TOPCONS

• Determine membrane orientation using the positive-inside rule

• Model embedding in a lipid bilayer using tools like CHARMM-GUI Membrane Builder

Functional Site Prediction:

• Identify conserved catalytic residues using ConSurf or Evolutionary Trace methods

• Predict binding sites using CASTp, COACH, or SiteMap

• Detect functional motifs using PROSITE, InterProScan, or Pfam

Molecular Dynamics Simulations:

• Embed the structural model in a membrane or solvent environment

• Simulate dynamics for at least 100 ns using GROMACS, NAMD, or AMBER

• Analyze conformational flexibility, stability, and potential conformational changes

• Identify allosteric communication pathways using network analysis

These computational approaches can provide substantial insights into YMF19's structural properties and potential functional mechanisms, particularly when integrated with evolutionary conservation data and experimental biochemical information . The resulting models can guide experimental design for mutagenesis studies, protein engineering, and functional assays.

How can multi-omics approaches advance our understanding of YMF19's role in sunflower biology?

Multi-omics approaches provide powerful tools for elucidating YMF19's role within the broader context of sunflower biology, offering a systems-level understanding that cannot be achieved through single-technique approaches. The following integrated methodology is recommended:

Transcriptomics Integration:

• Analyze YMF19 expression patterns across tissues, developmental stages, and stress conditions

• Identify co-expressed gene networks through:

  • Weighted Gene Co-expression Network Analysis (WGCNA)

  • Differential co-expression analysis

• Compare expression patterns across sunflower populations adapted to different environments to detect adaptive expression variation

• Correlate expression with environmental variables and phenotypic traits

Proteomics Approaches:

• Use targeted proteomics (SRM/MRM) to quantify YMF19 protein levels

• Employ affinity purification-mass spectrometry (AP-MS) to identify interaction partners

• Apply phosphoproteomics to detect regulatory post-translational modifications

• Use protein correlation profiling to identify complexes containing YMF19

Metabolomics Integration:

• Correlate YMF19 expression/activity with metabolite profiles

• Focus on energy metabolism intermediates and ATP/ADP ratios

• Identify metabolic signatures associated with YMF19 variation

• Map these correlations onto metabolic pathways to identify functional impacts

Genomic Variation Analysis:

• Identify natural variants in YMF19 across sunflower populations

• Associate these variants with phenotypic and environmental variables

• Target regions showing signatures of selection or association with adaptive traits

• Leverage the known genomic architecture of sunflower, including its high transposable element content

Integration Framework:

• Apply network-based data integration approaches:

  • Bayesian networks

  • Network component analysis

  • Multi-layer network models

• Use machine learning approaches to identify patterns across omics layers

• Develop predictive models of YMF19 function based on integrated data

This multi-omics approach is particularly powerful in the context of sunflower research, where adaptation to diverse environments has been studied through genome-wide association studies (GWAS) and environmental association analysis . By integrating YMF19 into these broader studies, researchers can understand its potential role in adaptive processes and position it within the complex regulatory and metabolic networks of the sunflower.

What are the emerging technologies that could advance our understanding of YMF19 function and regulation?

Several cutting-edge technologies are poised to transform our understanding of YMF19's function and regulation in Helianthus annuus. These approaches offer unprecedented resolution and insight into protein function within complex biological systems:

Cryo-Electron Microscopy (Cryo-EM):

• High-resolution structural determination of YMF19 within the native ATP synthase complex

• Visualization of conformational states during catalytic cycles

• Identification of interaction interfaces with other complex components

• Sample preparation advancements allowing for membrane protein complexes to be studied in near-native lipid environments

CRISPR-Cas9 Genome Editing in Sunflower:

• Generation of YMF19 knockout, knockdown, or precise mutation lines

• Creation of tagged versions for in vivo localization and interaction studies

• Implementation of base editing for specific amino acid changes

• Development of CRISPR interference/activation systems for controlled expression modulation

Single-Molecule Techniques:

• Single-molecule FRET to track conformational changes during ATP synthesis

• Optical tweezers to measure force generation and mechanical work

• Nanopore recording of ion translocation through YMF19-containing complexes

• Super-resolution microscopy for in situ visualization of complex assembly

Spatial Transcriptomics and Proteomics:

• Tissue-specific and subcellular mapping of YMF19 expression

• Correlation with metabolic states in different cell types

• Developmental trajectory analysis in specialized tissues

• Integration with physiological measurements for structure-function correlations

Synthetic Biology Approaches:

• Reconstitution of minimal ATP synthase systems with engineered YMF19 variants

• Design of switchable YMF19 variants responsive to external stimuli

• Creation of biosensors based on YMF19 conformational changes

• Integration into artificial organelles to study compartmentalized energy production

These emerging technologies, particularly when used in combination, promise to reveal the dynamic, context-dependent functions of YMF19 in sunflower biology . By leveraging these approaches, researchers can address fundamental questions about energy metabolism in plants and potentially develop applications in biotechnology and agriculture based on modulating ATP synthase function.

What implications does research on YMF19 have for understanding plant evolution and adaptation mechanisms?

Research on YMF19 offers significant insights into broader questions of plant evolution and adaptation mechanisms, particularly in the context of energy metabolism adaptation across diverse environments:

Evolutionary Conservation and Divergence:

YMF19 research provides a window into the evolution of energy production systems in plants. The presence of homologous proteins across diverse plant species—from liverworts (Marchantia polymorpha) to angiosperms (Helianthus annuus and Oenothera berteroana)—indicates the fundamental importance of this ATP synthase component . Comparative analysis can reveal:

• Functional constraints maintaining core catalytic functions across 400+ million years of plant evolution

• Lineage-specific adaptations potentially related to metabolic requirements in different ecological niches

• Co-evolution patterns with other components of the ATP synthase complex

Genomic Context and Genome Evolution:

The sunflower genome's unique composition, with over 81% transposable elements , provides valuable context for understanding how essential genes like YMF19 are maintained and regulated within highly dynamic genomes. This research can illuminate:

• Mechanisms protecting essential genes from disruption by transposable element activity

• Evolution of regulatory networks in the context of genome expansion and restructuring

• Impact of genome architecture on the adaptive potential of energy metabolism genes

Adaptation to Environmental Stressors:

Studies on sunflower adaptation have identified genomic regions associated with environmental variables such as number of frost-free days . YMF19 research can contribute to understanding:

• How energy metabolism adaptation contributes to environmental stress responses

• The role of ATP synthase components in local adaptation to diverse habitats

• Potential for engineered modifications to enhance stress tolerance

Convergent and Parallel Evolution:

Analysis of YMF19 across independently adapted sunflower populations can reveal:

• Whether similar modifications to energy metabolism have evolved repeatedly in response to similar selection pressures

• The relative importance of standing variation versus new mutations in ATP synthase adaptation

• Constraints and flexibility in the adaptation of fundamental cellular processes

Implications for Crop Improvement:

Understanding YMF19's role in energy production efficiency and stress responses has potential applications in sunflower crop improvement:

• Identification of natural variants associated with improved performance under stress conditions

• Development of molecular markers for energy efficiency traits

• Potential targets for precision breeding or engineering to enhance yield stability

The research on YMF19 thus contributes to our fundamental understanding of how essential cellular processes adapt and evolve while maintaining core functions, with implications spanning from evolutionary biology to applied crop improvement .