6A2S

Mycobacterium tuberculosis LexA C-domain S160A

6A2S の概要

• エントリーDOI: 10.2210/pdb6a2s/pdb
• 分子名称: LexA repressor, DI(HYDROXYETHYL)ETHER, HEXAETHYLENE GLYCOL, ... (4 entities in total)
• 機能のキーワード: mycobacterium tuberculosis, lexa, sos response, hydrolase
• 由来する生物種: Mycobacterium tuberculosis
• タンパク質・核酸の鎖数: 8
• 化学式量合計: 96218.85

構造登録者

Chandran, A.V.,Srikalaivani, R.,Paul, A.,Vijayan, M. (登録日: 2018-06-12, 公開日: 2019-01-23, 最終更新日: 2024-11-13)

主引用文献

Chandran, A.V.,Srikalaivani, R.,Paul, A.,Vijayan, M.
Biochemical characterization of Mycobacterium tuberculosis LexA and structural studies of its C-terminal segment.
Acta Crystallogr D Struct Biol, 75:41-55, 2019

PubMed Abstract: LexA is a protein that is involved in the SOS response. The protein from Mycobacterium tuberculosis and its mutants have been biochemically characterized and the structures of their catalytic segments have been determined. The protein is made up of an N-terminal segment, which includes the DNA-binding domain, and a C-terminal segment encompassing much of the catalytic domain. The two segments are defined by a cleavage site. Full-length LexA, the two segments, two point mutants involving changes in the active-site residues (S160A and K197A) and another mutant involving a change at the cleavage site (G126D) were cloned and purified. The wild-type protein autocleaves at basic pH, while the mutants do not. The wild-type and the mutant proteins dimerize and bind DNA with equal facility. The C-terminal segment also dimerizes, and it also shows a tendency to form tetramers. The C-terminal segment readily crystallized. The crystals obtained from attempts involving the full-length protein and its mutants contained only the C-terminal segment including the catalytic core and a few residues preceding it, in a dimeric or tetrameric form, indicating protein cleavage during the long period involved in crystal formation. Modes of tetramerization of the full-length protein similar to those observed for the catalytic core are feasible. A complex of M. tuberculosis LexA and the cognate SOS box could be modeled in which the mutual orientation of the two N-terminal domains differs from that in the Escherichia coli LexA-DNA complex. These results represent the first thorough characterization of M. tuberculosis LexA and provide definitive information on its structure and assembly. They also provide leads for further exploration of this important protein.

PubMed: 30644844
DOI: 10.1107/S2059798318016066

実験手法

X-RAY DIFFRACTION (2.5 Å)