2IBM

A novel dimer interface and conformational changes revealed by an X-ray structure of B. subtilis SecA

2IBM の概要

• エントリーDOI: 10.2210/pdb2ibm/pdb
• 関連するPDBエントリー: 1M6N 1NKT 1TF2
• 分子名称: Preprotein translocase secA subunit, ADENOSINE-5'-DIPHOSPHATE (2 entities in total)
• 機能のキーワード: protein translocation, seca, signal peptide binding, protein transport
• 由来する生物種: Bacillus subtilis
• 細胞内の位置: Cell membrane; Peripheral membrane protein; Cytoplasmic side (By similarity): P28366
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 178259.56

構造登録者

Zimmer, J.,Li, W.,Rapoport, T.A. (登録日: 2006-09-11, 公開日: 2006-11-14, 最終更新日: 2023-08-30)

主引用文献

Zimmer, J.,Li, W.,Rapoport, T.A.
A Novel Dimer Interface and Conformational Changes Revealed by an X-ray Structure of B. subtilis SecA.
J.Mol.Biol., 364:259-265, 2006

PubMed Abstract: The SecA ATPase moves polypeptides post-translationally across the plasma membrane of eubacteria, but the mechanism of transport is still unclear. We describe the crystal structure of a novel dimeric form of Bacillus subtilis SecA. Dimerization of SecA occurs at the prominent groove formed by the nucleotide binding domain 2 (nbd2) and the preprotein cross-linking (ppx) domain. The dimer interface is very large, burying approximately 5400 A(2) of solvent accessible surface per monomer. Single cysteine disulfide cross-linking shows the presence of this novel SecA dimer in solution. In addition, other dimers also exist in solution, arguing that they all are in equilibrium with monomeric SecA and supporting the idea that the monomer may be the functional species. Dimerization of SecA causes an alpha-helix of one subunit to convert to a short beta-strand that participates in beta-sheet formation with strands in the other subunit. This conversion of secondary structure elements occurs close to the connection between the nbd1 and ppx domains, a potential site of interaction with translocation substrate. Comparing the different X-ray structures of B. subtilis SecA suggests that small changes in the nucleotide binding domains could be amplified via helix 1 of the helical scaffold domain (hsd) to generate larger movements of the domains involved in polypeptide binding.

PubMed: 16989859
DOI: 10.1016/j.jmb.2006.08.044

実験手法

X-RAY DIFFRACTION (3.2 Å)