Elucidating the native architecture of the YidC: ribosome complex.
Membrane protein biogenesis in bacteria occurs via dedicated molecular systems SecYEG and YidC that function independently and in cooperation. YidC belongs to the universally conserved Oxa1/Alb3/YidC family of membrane insertases and is believed to associate with translating ribosomes at the membrane surface. Here, we have examined the architecture of the YidC:ribosome complex formed upon YidC-mediated membrane protein insertion. Fluorescence correlation spectroscopy was employed to investigate the complex assembly under physiological conditions. A slightly acidic environment stimulates binding of detergent-solubilized YidC to ribosomes due to electrostatic interactions, while YidC acquires specificity for translating ribosomes at pH-neutral conditions. The nanodisc reconstitution of the YidC to embed it into a native phospholipid membrane environment strongly enhances the YidC:ribosome complex formation. A single copy of YidC suffices for the binding of translating ribosome both in detergent and at the lipid membrane interface, thus being the minimal functional unit. Data reveal molecular details on the insertase functioning and interactions and suggest a new structural model for the YidC:ribosome complex.
Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, and Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands. Electronic address: Kedrov@genzentrum.lmu.de.
Alexej
A
Kedrov
Marko
M
Sustarsic
Jeanine
J
de Keyzer
Joseph J
JJ
Caumanns
Zht Cheng
ZC
Wu
Arnold J M
AJ
Driessen
D003902:Detergents / Q000737:chemistry; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D055503:Protein Multimerization; D012270:Ribosomes / Q000737:chemistry* / Q000378:metabolism; D012996:Solutions / Q000737:chemistry
D003902:Detergents; D029968:Escherichia coli Proteins; D008051:Lipid Bilayers; D026901:Membrane Transport Proteins; D046912:Multiprotein Complexes; D012996:Solutions; C412443:YIDC protein, E coli
DDM; FCCS; FCS; FRET; Förster resonance energy transfer; MSP; RNC; cryo-EM; cryo-electron microscopy; fluorescence correlation spectroscopy; fluorescence cross-correlation spectroscopy; macromolecular assembly; major scaffold protein; membrane insertase; membrane protein; n-dodecyl β-d-maltoside; ribosome; ribosome:nascent chain; single-molecule biophysics