1L9T

CRYSTAL STRUCTURE OF THE I257V VARIANT OF THE COPPER-CONTAINING NITRITE REDUCTASE FROM ALCALIGENES FAECALIS S-6

1L9T の概要

• エントリーDOI: 10.2210/pdb1l9t/pdb
• 関連するPDBエントリー: 1L9O 1L9P 1L9Q 1L9R 1L9S
• 分子名称: COPPER-CONTAINING NITRITE REDUCTASE, COPPER (II) ION, NITRITE ION, ... (4 entities in total)
• 機能のキーワード: cupredoxin fold, oxidoreductase
• 由来する生物種: Alcaligenes faecalis
• 細胞内の位置: Periplasm: P38501
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 111113.15

構造登録者

Boulanger, M.J.,Murphy, M.E.P. (登録日: 2002-03-26, 公開日: 2003-02-04, 最終更新日: 2024-02-14)

主引用文献

Boulanger, M.J.,Murphy, M.E.P.
Directing the mode of nitrite binding to a copper-containing nitrite reductase from Alcaligenes faecalis S-6: Characterization of an active site isoleucine
PROTEIN SCI., 12:248-256, 2003

PubMed Abstract: Unlike the heme cd(1)-based nitrite reductase enzymes, the molecular mechanism of copper-containing nitrite reductases remains controversial. A key source of controversy is the productive binding mode of nitrite in the active site. To identify and characterize the molecular determinants associated with nitrite binding, we applied a combinatorial mutagenesis approach to generate a small library of six variants at position 257 in nitrite reductase from Alcaligenes faecalis S-6. The activities of these six variants span nearly two orders of magnitude with one variant, I257V, the only observed natural substitution for Ile257, showing greater activity than the native enzyme. High-resolution (> 1.8 A) nitrite-soaked crystal structures of these variants display different modes of nitrite binding that correlate well with the altered activities. These studies identify for the first time that the highly conserved Ile257 in the native enzyme is a key molecular determinant in directing a catalytically competent mode of nitrite binding in the active site. The O-coordinate bidentate binding mode of nitrite observed in native and mutant forms with high activity supports a catalytic model distinct from the heme cd(1) NiRs. (The atomic coordinates for I257V[NO(2)(-)], I257L[NO(2)(-)], I257A[NO(2)(-)], I257T[NO(2)(-)], I257M[NO(2)(-)] and I257G[NO(2)(-)] AfNiR have been deposited in the Protein Data Bank [PDB identification codes are listed in Table 2].)

PubMed: 12538888
DOI: 10.1110/ps.0224503

実験手法

X-RAY DIFFRACTION (1.75 Å)