5MG3

EM fitted model of bacterial holo-translocon

Summary for 5MG3

• Entry DOI: 10.2210/pdb5mg3/pdb
• EMDB information: 3506
• Descriptor: Protein translocase subunit SecY, Protein translocase subunit SecE, Protein-export membrane protein SecG, ... (6 entities in total)
• Functional Keywords: holotranslocon, membrane protein insertion machinery, chaperone, protein secretion
• Biological source: Escherichia coli; More
• Cellular location: Cell inner membrane; Multi-pass membrane protein: P0AGA2 P0AG96 P0AG99 P0AG90 P0AG93 P25714
• Total number of polymer chains: 6
• Total formula weight: 245744.81

Authors

Schaffitzel, C.,Botte, M. (deposition date: 2016-11-20, release date: 2016-12-28, Last modification date: 2024-11-20)

Primary citation

Botte, M.,Zaccai, N.R.,Nijeholt, J.L.,Martin, R.,Knoops, K.,Papai, G.,Zou, J.,Deniaud, A.,Karuppasamy, M.,Jiang, Q.,Roy, A.S.,Schulten, K.,Schultz, P.,Rappsilber, J.,Zaccai, G.,Berger, I.,Collinson, I.,Schaffitzel, C.
A central cavity within the holo-translocon suggests a mechanism for membrane protein insertion.
Sci Rep, 6:38399-38399, 2016

PubMed Abstract: The conserved SecYEG protein-conducting channel and the accessory proteins SecDF-YajC and YidC constitute the bacterial holo-translocon (HTL), capable of protein-secretion and membrane-protein insertion. By employing an integrative approach combining small-angle neutron scattering (SANS), low-resolution electron microscopy and biophysical analyses we determined the arrangement of the proteins and lipids within the super-complex. The results guided the placement of X-ray structures of individual HTL components and allowed the proposal of a model of the functional translocon. Their arrangement around a central lipid-containing pool conveys an unexpected, but compelling mechanism for membrane-protein insertion. The periplasmic domains of YidC and SecD are poised at the protein-channel exit-site of SecY, presumably to aid the emergence of translocating polypeptides. The SecY lateral gate for membrane-insertion is adjacent to the membrane 'insertase' YidC. Absolute-scale SANS employing a novel contrast-match-point analysis revealed a dynamic complex adopting open and compact configurations around an adaptable central lipid-filled chamber, wherein polytopic membrane-proteins could fold, sheltered from aggregation and proteolysis.

PubMed: 27924919
DOI: 10.1038/srep38399

Experimental method

ELECTRON MICROSCOPY (14 Å)