Projection structure of yidC: a conserved mediator of membrane protein assembly.
Bacteria, mitochondria and chloroplasts harbour factors that facilitate the insertion, folding and assembly of membrane proteins. In Escherichia coli, yidC is required for membrane insertion, acting in both a Sec-dependent and a Sec-independent manner. There is an expanding volume of biochemical work on its role in this process, but none so far on its structure. We present the first of this class of membrane proteins determined by electron cryomicroscopy in the near-nativelike state of the membrane. yidC forms dimers in the membrane and each monomer has an area of low density that may be part of the path transmembrane segments follow during their insertion. Upon consideration of the structures of yidC and SecYEG, we speculate on the nature of the interfaces that facilitate the alternative pathways (Sec-dependent and -independent) of membrane protein insertion.
Lotz
Mirko
M
Max Planck Institute of Biophysics, Max-von-Laue-Strasse 3, D-60438 Frankfurt am Main, Germany.
Haase
Winfried
W
Kühlbrandt
Werner
W
Collinson
Ian
I
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000911:Antibodies, Monoclonal / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D019281:Dimerization; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D005583:Fourier Analysis; D006046:Gold / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D008954:Models, Biological; D008956:Models, Chemical; D008970:Molecular Weight; D011499:Protein Processing, Post-Translational; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D000069816:SEC Translocation Channels; D000081416:SecA Proteins; D018271:Signal Recognition Particle / Q000378:metabolism; D013379:Substrate Specificity
D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D000069816:SEC Translocation Channels; C057842:SecB protein, Bacteria; D018271:Signal Recognition Particle; C412443:YIDC protein, E coli; D006046:Gold; D000251:Adenosine Triphosphatases; D000081416:SecA Proteins