The conserved third transmembrane segment of YidC contacts nascent Escherichia coli inner membrane proteins.
Escherichia coli YidC is a polytopic inner membrane protein that plays an essential and versatile role in the biogenesis of inner membrane proteins. YidC functions in Sec-dependent membrane insertion but acts also independently as a separate insertase for certain small membrane proteins. We have used a site-specific cross-linking approach to show that the conserved third transmembrane segment of YidC contacts the transmembrane domains of both nascent Sec-dependent and -independent substrates, indicating a generic recognition of insertion intermediates by YidC. Our data suggest that specific residues of the third YidC transmembrane segment alpha-helix is oriented toward the transmembrane domains of nascent inner membrane proteins that, in contrast, appear quite flexibly positioned at this stage in biogenesis.
Department of Molecular Microbiology, Institute of Molecular Cell Biology, VU University, de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.
Zhong
Z
Yu
Gregory
G
Koningstein
Ana
A
Pop
Joen
J
Luirink
D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000378:metabolism*; D003432:Cross-Linking Reagents / Q000737:chemistry; D003545:Cysteine / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D008055:Lipids / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
D003432:Cross-Linking Reagents; D029968:Escherichia coli Proteins; D008055:Lipids; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C412443:YIDC protein, E coli; D003545:Cysteine