6itc

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Structure of a substrate engaged SecA-SecY protein translocation machine

Structural highlights

6itc is a 7 chain structure with sequence from Aequorea victoria, Bacillus subtilis subsp. subtilis str. 168, Escherichia coli, Geobacillus thermodenitrificans NG80-2 and Lama glama. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:Electron Microscopy, Resolution 3.45Å
Experimental data:Check to display Experimental Data
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

SECA_BACSU Part of the Sec protein translocase complex. Interacts with the SecYEG preprotein conducting channel. Has a central role in coupling the hydrolysis of ATP to the transfer of proteins into and across the cell membrane, serving as an ATP-driven molecular motor driving the stepwise translocation of polypeptide chains across the membrane (By similarity).[HAMAP-Rule:MF_01382]

Publication Abstract from PubMed

The Sec61/SecY channel allows the translocation of many proteins across the eukaryotic endoplasmic reticulum membrane or the prokaryotic plasma membrane. In bacteria, most secretory proteins are transported post-translationally through the SecY channel by the SecA ATPase. How a polypeptide is moved through the SecA-SecY complex is poorly understood, as structural information is lacking. Here, we report an electron cryo-microscopy (cryo-EM) structure of a translocating SecA-SecY complex in a lipid environment. The translocating polypeptide chain can be traced through both SecA and SecY. In the captured transition state of ATP hydrolysis, SecA's two-helix finger is close to the polypeptide, while SecA's clamp interacts with the polypeptide in a sequence-independent manner by inducing a short beta-strand. Taking into account previous biochemical and biophysical data, our structure is consistent with a model in which the two-helix finger and clamp cooperate during the ATPase cycle to move a polypeptide through the channel.

Structure of the substrate-engaged SecA-SecY protein translocation machine.,Ma C, Wu X, Sun D, Park E, Catipovic MA, Rapoport TA, Gao N, Li L Nat Commun. 2019 Jun 28;10(1):2872. doi: 10.1038/s41467-019-10918-2. PMID:31253804[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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See Also

References

  1. Ma C, Wu X, Sun D, Park E, Catipovic MA, Rapoport TA, Gao N, Li L. Structure of the substrate-engaged SecA-SecY protein translocation machine. Nat Commun. 2019 Jun 28;10(1):2872. doi: 10.1038/s41467-019-10918-2. PMID:31253804 doi:http://dx.doi.org/10.1038/s41467-019-10918-2

Contents


6itc, resolution 3.45Å

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