title: The C-terminal regions of YidC from Rhodopirellula baltica and Oceanicaulis alexandrii bind to ribosomes and partially substitute for SRP receptor function in Escherichia coli.
abstract: The marine Gram-negative bacteria Rhodopirellula baltica and Oceanicaulis alexandrii have, in contrast to Escherichia coli, membrane insertases with extended positively charged C-terminal regions similar to the YidC homologues in mitochondria and Gram-positive bacteria. We have found that chimeric forms of E. coli YidC fused to the C-terminal YidC regions from the marine bacteria mediate binding of YidC to ribosomes and therefore may have a functional role for targeting a nascent protein to the membrane. Here, we show in E. coli that an extended C-terminal region of YidC can compensate for a loss of SRP-receptor function in vivo. Furthermore, the enhanced affinity of the ribosome to the chimeric YidC allows the isolation of a ribosome nascent chain complex together with the C-terminally elongated YidC chimera. This complex was visualized at 8.6 Å by cryo-electron microscopy and shows a close contact of the ribosome and a YidC monomer.
authors.affiliation: Institute of Microbiology and Molecular Biology, University of Hohenheim, 70599, Stuttgart, Germany.
authors.forename: Ines
authors.initials: I
authors.lastname: Seitl
authors.forename: Stephan
authors.initials: S
authors.lastname: Wickles
authors.forename: Roland
authors.initials: R
authors.lastname: Beckmann
authors.forename: Andreas
authors.initials: A
authors.lastname: Kuhn
authors.forename: Dorothee
authors.initials: D
authors.lastname: Kiefer
mesh_terms: D020561:Alphaproteobacteria / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020285:Cryoelectron Microscopy; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D061328:Planctomycetales / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018000:Receptors, Peptide / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C087406:FtsY protein, Bacteria; D008565:Membrane Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D018000:Receptors, Peptide; D011993:Recombinant Fusion Proteins; C036318:signal peptide receptor