Recombinant Sinorhizobium medicae Membrane protein insertase YidC (yidC)
Description
Introduction to YidC in Bacterial Membrane Biogenesis
YidC is a universally conserved membrane protein insertase critical for the integration, folding, and assembly of membrane proteins. It operates both independently and in conjunction with the Sec translocase . In Sinorhizobium medicae, a nitrogen-fixing symbiont of legumes like Medicago polymorpha, YidC is hypothesized to play a key role in the biogenesis of membrane proteins essential for symbiosis and environmental adaptation .
Core Mechanism
YidC facilitates the insertion of Sec-independent substrates via a hydrophilic groove that interacts with hydrophobic transmembrane domains (TMDs) of nascent proteins . This groove enables dehydration and lipid partitioning, critical for proper protein topology .
Evolutionary Conservation
YidC homologs exist across bacteria, mitochondria (Oxa1), chloroplasts (Alb3), and eukaryotes (EMC3, TMCO1) . Sinorhizobium medicae YidC shares this conserved architecture, inferred from genomic synteny and functional studies in related rhizobia .
Symbiotic Nitrogen Fixation
Sinorhizobium medicae forms nodules on Medicago roots, requiring membrane proteins for nutrient exchange and stress tolerance . YidC likely mediates the insertion of:
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Nodulation (Nod) factors: Surface receptors for host recognition.
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Respiratory complexes: Energy production under microaerobic nodule conditions .
Environmental Adaptation
S. medicae thrives in diverse soil conditions, correlating with YidC-dependent membrane protein folding . For example:
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Acid tolerance: YidC may stabilize pH-responsive transporters .
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Oxidative stress: Insertion of redox enzymes (e.g., cytochrome oxidases) .
Expression Systems
While Sinorhizobium medicae YidC has not been directly purified, homologous studies in E. coli provide a roadmap:
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Cloning: yidC is expressed with a His-tag for affinity purification .
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Reconstitution: Proteoliposomes containing YidC enable in vitro insertion assays .
Functional Assays
Research Gaps and Future Directions
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Structural Characterization: No high-resolution structure exists for S. medicae YidC; cryo-EM or crystallography is needed .
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Substrate Specificity: Role in symbiosis-related proteins (e.g., Nod factors) remains untested .
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Regulatory Partners: Identification of S. medicae homologs of YibN, a YidC interactor enhancing substrate insertion .
Product Specs
Note: We will prioritize shipping the format that we have in stock. However, if you have a specific format requirement, please indicate it in your order notes. We will prepare your order accordingly.
Note: All of our proteins are shipped with standard blue ice packs. If you require dry ice shipping, please contact us in advance as additional fees will apply.
Generally, the shelf life of liquid form is 6 months at -20°C/-80°C. The shelf life of lyophilized form is 12 months at -20°C/-80°C.
Target Background
KEGG: smd:Smed_0079
STRING: 366394.Smed_0079
Q&A
Basic Research Questions
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What is YidC and what is its fundamental function in bacterial membranes?
YidC is a highly conserved membrane protein insertase that facilitates the insertion and folding of proteins into bacterial cytoplasmic membranes. It functions through two primary mechanisms: (1) independently as a dedicated insertase for specific substrates (YidC-only pathway) and (2) cooperatively with the SecYEG translocon complex. Beyond insertion, YidC also acts as a foldase that promotes proper assembly of membrane protein complexes . The protein contains a hydrophilic groove that opens toward the cytoplasm and reaches halfway through the lipid bilayer, forming the essential functional domain for substrate interaction and translocation .
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How does the YidC structure enable its insertase function?
The crystal structure of YidC reveals several key structural features that facilitate its function:
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A coiled-coil domain in the cytoplasmic loop C1
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Five core transmembrane α-helices forming a hydrophilic groove accessible from both the cytoplasm and lipid bilayer
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A "greasy slide" comprised of transmembrane α-helices III and V
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Short lipid-exposed transmembrane helices (3, 4, and 5) that cause membrane thinning around YidC
During insertion, the nascent amino-terminal hydrophilic segment initially binds to the cytoplasmic loop C1, which guides it to the hydrophilic groove. This groove accommodates hydrophilic segments for translocation through the lipid membrane, while the hydrophobic transmembrane α-helices interact with the greasy slide to facilitate membrane insertion .
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What is known about Sinorhizobium medicae YidC sequence and structure?
The Sinorhizobium medicae YidC (strain WSM419) protein consists of 597 amino acids with the following characteristics:
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UniProt accession number: A6U5K9
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Gene locus name: Smed_0079
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Contains highly conserved functional domains typical of the YidC/Oxa1/Alb3 family
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Shares approximately 95% sequence similarity with YidC from other Gram-negative bacteria like E. coli and S. typhimurium
The protein contains multiple transmembrane segments and characteristic cytoplasmic and periplasmic domains essential for its insertase and foldase functions.
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