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.
Yu
Zhong
Z
Department of Molecular Microbiology, Institute of Molecular Cell Biology, VU University, de Boelelaan 1085, 1081 HV Amsterdam, The Netherlands.
Koningstein
Gregory
G
Pop
Ana
A
Luirink
Joen
J
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