Recombinant Synechocystis sp. Membrane protein insertase YidC (yidC)
Description
Definition and Biological Context
Recombinant YidC is a 61 kDa inner membrane protein (UniProt ID: P74155) expressed in Escherichia coli for research applications . It belongs to the YidC/Oxa1/Alb3 family of insertases, which facilitate the integration of transmembrane domains into lipid bilayers . In Synechocystis sp. PCC 6803, the native YidC homolog (Slr1471p) is essential for cell viability, thylakoid membrane biogenesis, and photochemical efficiency .
Functional Roles
YidC mediates two primary functions:
-
Membrane Protein Insertion: Facilitates cotranslational integration of hydrophobic segments into lipid bilayers, either independently or alongside the Sec translocon .
-
Respiratory and Photosynthetic Complex Assembly: Directly interacts with electron transport chain components (e.g., succinate dehydrogenase) and photosystem II proteins (e.g., D1 precursor) . Depletion disrupts ATP synthesis and redox balance in Synechocystis .
Production and Purification
Recombinant YidC is produced under optimized conditions:
Product Specs
Note: While we prioritize shipping the format currently in stock, please specify your preferred format in order notes for customized preparation.
Note: Standard shipping includes blue ice packs. Dry ice shipping requires prior arrangement and incurs additional charges.
If a specific tag type is required, please inform us for preferential development.
Target Background
KEGG: syn:slr1471
STRING: 1148.SYNGTS_1669
Q&A
Basic Research Questions
-
What is the functional role of YidC in Synechocystis sp. membrane protein biogenesis?
YidC in Synechocystis sp. (Slr1471p homolog) is essential for the integration and assembly of thylakoid membrane proteins, including the D1 subunit of Photosystem II . Methodologically, studies employ GFP-tagged mutants (slr1471-gfp) to demonstrate that YidC depletion disrupts D1 precursor (pD1) membrane insertion, leading to photoinhibition under high light (≥80 μmol·m⁻²·s⁻¹) . Researchers validate this via redox analysis of quinone molecules (Qₐ⁻ and Qʙ⁻), showing altered electron transport efficiency in mutants . Cross-linking assays further confirm direct YidC-pD1 interactions, highlighting its chaperone-like role in stabilizing assembly intermediates .
-
How do researchers distinguish YidC’s insertase activity from SecYEG-dependent pathways?
Functional partitioning is analyzed using in vitro reconstitution assays. For example, purified YidC proteoliposomes are incubated with model substrates like Pf3 coat protein to assess Sec-independent insertion . Single-molecule force spectroscopy reveals YidC binds Pf3’s cytoplasmic α-helical hairpin within 2 ms, followed by conformational stabilization into transmembrane helices within 52 ms . Control experiments using SecYEG-deficient strains or inhibitors (e.g., sodium azide for SecA ATPase inhibition) further isolate YidC-specific activity .
-
What experimental models are used to study YidC’s structural dynamics?
Cryo-EM and molecular dynamics (MD) simulations dominate structural studies. For instance, equilibrium MD of Synechocystis YidC-Pf3 complexes reveals that RMSD fluctuations ≥2 Å in YidC’s transmembrane groove correlate with substrate insertion stages . Steered MD simulations quantify energy barriers (~50 kJ/mol) for Pf3 translocation, emphasizing the role of hydrophilic residues in YidC’s groove during dehydration-rehydration cycles . Comparative models of E. coli YidC and Synechocystis Slr1471p further identify conserved motifs, such as the C1 loop critical for SecYEG interaction .
Advanced Research Questions
-
What methodologies identify YidC’s role in resolving membrane protein folding intermediates?
Fluorescence resonance energy transfer (FRET) between YidC and nascent chains (e.g., leader peptidase) captures real-time folding kinetics. A 40% FRET efficiency decrease in YidC-depleted strains indicates impaired helix-helix packing . Additionally, hydrogen-deuterium exchange mass spectrometry (HDX-MS) maps protected regions in YidC-bound Pf3, showing reduced solvent accessibility in transmembrane domains versus cytoplasmic regions .
-
How do researchers validate YidC’s evolutionary conservation across bacterial species?
Phylogenetic analysis of 450+ YidC homologs identifies a conserved three-transmembrane-helix (TMH) core (TMH1/4/5) shared with SecY . Functional complementation assays show Arabidopsis Alb3 rescues E. coli ΔyidC lethality, while Synechocystis Slr1471p fails to complement mitochondrial Δoxa1, highlighting clade-specific adaptations . Structural alignment (PyMOL) further confirms TMH1-4-5 topology in YidC and SecY, with RMSD <3.5 Å over Cα atoms .
Data Table: Key Experimental Findings on Synechocystis YidC
Methodological Challenges and Solutions
-
What are the technical hurdles in purifying active recombinant YidC?
YidC’s hydrophobicity necessitates detergent screening for solubility. Synechocystis YidC is optimally extracted in 1.5% n-dodecyl-β-D-maltoside (DDM), retaining 80% activity after immobilization on Ni-NTA resins . Circular dichroism (CD) confirms α-helix preservation (55% helicity), while activity assays monitor pD1 integration into proteoliposomes . Contaminant removal requires gradient centrifugation (10–30% sucrose) and size-exclusion chromatography (Superdex 200) .
Future Directions
-
What advanced techniques could elucidate YidC’s conformational dynamics?
Time-resolved cryo-EM with sub-second mixing devices (e.g., Spotiton) may capture pre-insertion states. Single-molecule fluorescence tracking using HaloTag-YidC fusions could map spatial coordination with SecYEG in vivo. Additionally, machine learning models trained on MD trajectories (e.g., AlphaFold-Multimer) may predict substrate recognition motifs .
-
How can YidC studies inform engineering of synthetic membrane protein systems?
Rational design of YidC variants (e.g., C1 loop mutations) could enhance substrate specificity. For example, substituting YidC Gly399 with bulky residues (e.g., Trp) reduces SecYEG binding by 70%, enabling isolation of YidC-only insertion pathways . Such variants may facilitate de novo membrane protein assembly in artificial cells or biosensors .
