1P3W

X-ray crystal structure of E. coli IscS

1P3W の概要

• エントリーDOI: 10.2210/pdb1p3w/pdb
• 分子名称: Cysteine desulfurase, PYRIDOXAL-5'-PHOSPHATE (3 entities in total)
• 機能のキーワード: iron sulfur cluster, nifs, csdb, lyase
• 由来する生物種: Escherichia coli
• 細胞内の位置: Cytoplasm : P0A6B7
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 90793.24

構造登録者

Cupp-Vickery, J.R.,Vickery, L.E.,Urbina, H. (登録日: 2003-04-18, 公開日: 2003-07-22, 最終更新日: 2024-04-03)

主引用文献

Cupp-Vickery, J.R.,Urbina, H.,Vickery, L.E.
Crystal Structure of IscS, a Cysteine Desulfurase from Escherichia coli
J.Mol.Biol., 330:1049-1059, 2003

PubMed Abstract: IscS is a widely distributed cysteine desulfurase that catalyzes the pyridoxal phosphate-dependent desulfuration of L-cysteine and plays a central role in the delivery of sulfur to a variety of metabolic pathways. We report the crystal structure of Escherichia coli IscS to a resolution of 2.1A. The crystals belong to the space group P2(1)2(1)2(1) and have unit cell dimensions a=73.70A, b=101.97A, c=108.62A (alpha=beta=gamma=90 degrees ). Molecular replacement with the Thermotoga maritima NifS model was used to determine phasing, and the IscS model was refined to an R=20.6% (R(free)=23.6%) with two molecules per asymmetric unit. The structure of E.coli IscS is similar to that of T.maritima NifS with nearly identical secondary structure and an overall backbone r.m.s. difference of 1.4A. However, in contrast to NifS a peptide segment containing the catalytic cysteine residue (Cys328) is partially ordered in the IscS structure. This segment of IscS (residues 323-335) forms a surface loop directed away from the active site pocket. Cys328 is positioned greater than 17A from the pyridoxal phosphate cofactor, suggesting that a large conformational change must occur during catalysis in order for Cys328 to participate in nucleophilic attack of a pyridoxal phosphate-bound cysteine substrate. Modeling suggests that rotation of this loop may allow movement of Cys328 to within approximately 3A of the pyridoxal phosphate cofactor.

PubMed: 12860127
DOI: 10.1016/S0022-2836(03)00690-9

実験手法

X-RAY DIFFRACTION (2.1 Å)