3JUX

Structure of the translocation ATPase SecA from Thermotoga maritima

3JUX の概要

• エントリーDOI: 10.2210/pdb3jux/pdb
• 分子名称: Protein translocase subunit secA, MAGNESIUM ION, ADENOSINE-5'-DIPHOSPHATE, ... (4 entities in total)
• 機能のキーワード: protein translocation, atpase, conformational change, peptide binding, atp-binding, cell inner membrane, cell membrane, cytoplasm, membrane, nucleotide-binding, protein transport, translocation, transport
• 由来する生物種: Thermotoga maritima
• 細胞内の位置: Cell inner membrane; Peripheral membrane protein; Cytoplasmic side (By similarity): Q9X1R4
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 95375.50

構造登録者

Zimmer, J. (登録日: 2009-09-15, 公開日: 2009-10-20, 最終更新日: 2023-09-06)

主引用文献

Zimmer, J.,Rapoport, T.A.
Conformational flexibility and peptide interaction of the translocation ATPase SecA.
J.Mol.Biol., 394:606-612, 2009

PubMed Abstract: The SecA ATPase forms a functional complex with the protein-conducting SecY channel to translocate polypeptides across the bacterial cell membrane. SecA recognizes the translocation substrate and catalyzes its unidirectional movement through the SecY channel. The recent crystal structure of the Thermotoga maritima SecA-SecYEG complex shows the ATPase in a conformation where the nucleotide-binding domains (NBDs) have closed around a bound ADP-BeFx complex and SecA's polypeptide-binding clamp is shut. Here, we present the crystal structure of T. maritima SecA in isolation, determined in its ADP-bound form at 3.1 A resolution. SecA alone has a drastically different conformation in which the nucleotide-binding pocket between NBD1 and NBD2 is open and the preprotein cross-linking domain has rotated away from both NBDs, thereby opening the polypeptide-binding clamp. To investigate how this clamp binds polypeptide substrates, we also determined a structure of Bacillus subtilis SecA in complex with a peptide at 2.5 A resolution. This structure shows that the peptide augments the highly conserved beta-sheet at the back of the clamp. Taken together, these structures suggest a mechanism by which ATP hydrolysis can lead to polypeptide translocation.

PubMed: 19850053
DOI: 10.1016/j.jmb.2009.10.024

実験手法

X-RAY DIFFRACTION (3.1 Å)