The structure of the bacterial protein translocation complex SecYEG

被引:12
作者
Collinson, I [1 ]
机构
[1] Univ Bristol, Dept Biochem, Bristol BS8 1TD, Avon, England
关键词
membrane protein; protein translocation; secretion; SecYEG; translocon;
D O I
10.1042/BST0331225
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Proteins destined for secretion, membrane insertion or organellar import contain signal sequences that direct them to the membrane. Once there, transport machines receive and translocate them appropriately across or into the membrane. The related SecY and Sec61 protein translocation complexes are ubiquitous components of machines that are essential for protein transport. They co-operate with various partners such that the substrate polypepticle is pulled or pushed through the membrane by post- or co-translational mechanisms. in bacteria and archaea, the SecY complex (SecYEG/SecYE beta) is a heterotrimer which associates with ribosomes so that the polypeptide is threaded through the channel during. its synthesis. Bacteria possess an additional pathway, whereby the newly synthesized substrate protein is maintained in an unfolded conformation and is engaged by the ATPase SecA and delivered to the translocon. Recent medium- (cryo-electron microscopy) and high-resolution (X-ray) structures of the Sec complex have dramatically increased our understanding about how proteins pass through membranes, but have posed a number of new questions. The Sec complex is active as an oligomer, but the structure indicates that the protein-conducting channel is formed by a monomer of SecYEG. Structures of the membrane-bound dimer of Escherichia coli SecYEG and the detergent-solubilized monomer of Methanococcus jannaschii SecYE beta will be described and discussed in the context of the mechanism that underlies protein secretion and membrane insertion.
引用
收藏
页码:1225 / 1230
页数:6
相关论文
共 49 条
[1]   Three-dimensional map of the plasma membrane H+-ATPase in the open conformation [J].
Auer, M ;
Scarborough, GA ;
Kühlbrandt, W .
NATURE, 1998, 392 (6678) :840-843
[2]   Architecture of the protein-conducting channel associated with the translating 80S ribosome [J].
Beckmann, R ;
Spahn, CMT ;
Eswar, N ;
Helmers, J ;
Penczek, PA ;
Sali, A ;
Frank, J ;
Blobel, G .
CELL, 2001, 107 (03) :361-372
[3]   Alignment of conduits for the nascent polypeptide chain in the Ribosome-Sec61 complex [J].
Beckmann, R ;
Bubeck, D ;
Grassucci, R ;
Penczek, P ;
Verschoor, A ;
Blobel, G ;
Frank, J .
SCIENCE, 1997, 278 (5346) :2123-2126
[4]   The SecYEG preprotein translocation channel is a conformationally dynamic and dimeric structure [J].
Bessonneau, P ;
Besson, V ;
Collinson, I ;
Duong, F .
EMBO JOURNAL, 2002, 21 (05) :995-1003
[5]   Three-dimensional structure of the bacterial protein-translocation complex SecYEG [J].
Breyton, C ;
Haase, W ;
Rapoport, TA ;
Kühlbrandt, W ;
Collinson, I .
NATURE, 2002, 418 (6898) :662-665
[6]   THE PURIFIED ESCHERICHIA-COLI INTEGRAL MEMBRANE-PROTEIN SECY/E IS SUFFICIENT FOR RECONSTITUTION OF SECA-DEPENDENT PRECURSOR PROTEIN TRANSLOCATION [J].
BRUNDAGE, L ;
HENDRICK, JP ;
SCHIEBEL, E ;
DRIESSEN, AJM ;
WICKNER, W .
CELL, 1990, 62 (04) :649-657
[7]   Disulfide bridge formation between SecY and a translocating polypeptide localizes the translocation pore to the center of SecY [J].
Cannon, KS ;
Or, E ;
Clemons, WM ;
Shibata, Y ;
Rapoport, TA .
JOURNAL OF CELL BIOLOGY, 2005, 169 (02) :219-225
[8]   Projection structure and oligomeric properties of a bacterial core protein translocase [J].
Collinson, I ;
Breyton, C ;
Duong, F ;
Tziatzios, C ;
Schubert, D ;
Or, E ;
Rapoport, T ;
Kühlbrandt, W .
EMBO JOURNAL, 2001, 20 (10) :2462-2471
[9]   SECA, THE PERIPHERAL SUBUNIT OF THE ESCHERICHIA-COLI PRECURSOR PROTEIN TRANSLOCASE, IS FUNCTIONAL AS A DIMER [J].
DRIESSEN, AJM .
BIOCHEMISTRY, 1993, 32 (48) :13190-13197
[10]   Binding, activation and dissociation of the dimeric SecA ATPase at the dimeric SecYEG translocase [J].
Duong, F .
EMBO JOURNAL, 2003, 22 (17) :4375-4384