1YLU

The structure of E. coli nitroreductase with bound acetate, crystal form 2

1YLU の概要

• エントリーDOI: 10.2210/pdb1ylu/pdb
• 関連するPDBエントリー: 1ICR 1ICU 1ICV 1YKI 1YLR
• 分子名称: Oxygen-insensitive NAD(P)H nitroreductase, ACETATE ION, FLAVIN MONONUCLEOTIDE, ... (4 entities in total)
• 機能のキーワード: oxidoreductase, oxygen-insensitive nad(p)h nitroreductase
• 由来する生物種: Escherichia coli
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 48964.18

構造登録者

Race, P.R.,Lovering, A.L.,Green, R.M.,Ossor, A.,White, S.A.,Searle, P.F.,Wrighton, C.J.,Hyde, E.I. (登録日: 2005-01-19, 公開日: 2005-02-08, 最終更新日: 2023-08-23)

主引用文献

Race, P.R.,Lovering, A.L.,Green, R.M.,Ossor, A.,White, S.A.,Searle, P.F.,Wrighton, C.J.,Hyde, E.I.
Structural and mechanistic studies of Escherichia coli nitroreductase with the antibiotic nitrofurazone. Reversed binding orientations in different redox states of the enzyme.
J.Biol.Chem., 280:13256-13264, 2005

PubMed Abstract: The antibiotics nitrofurazone and nitrofurantoin are used in the treatment of genitourinary infections and as topical antibacterial agents. Their action is dependent upon activation by bacterial nitroreductase flavoproteins, including the Escherichia coli nitroreductase (NTR). Here we show that the products of reduction of these antibiotics by NTR are the hydroxylamine derivatives. We show that the reduction of nitrosoaromatics is enzyme-catalyzed, with a specificity constant approximately 10,000-fold greater than that of the starting nitro compounds. This suggests that the reduction of nitro groups proceeds through two successive, enzyme-mediated reactions and explains why the nitroso intermediates are not observed. The global reaction rate for nitrofurazone determined in this study is over 10-fold higher than that previously reported, suggesting that the enzyme is much more active toward nitroaromatics than previously estimated. Surprisingly, in the crystal structure of the oxidized NTR-nitrofurazone complex, nitrofurazone is oriented with its amide group, rather than the nitro group to be reduced, positioned over the reactive N5 of the FMN cofactor. Free acetate, which acts as a competitive inhibitor with respect to NADH, binds in a similar orientation. We infer that the orientation of bound nitrofurazone depends upon the redox state of the enzyme. We propose that the charge distribution on the FMN rings, which alters upon reduction, is an important determinant of substrate binding and reactivity in flavoproteins with broad substrate specificity.

PubMed: 15684426
DOI: 10.1074/jbc.M409652200

実験手法

X-RAY DIFFRACTION (2 Å)