当前位置： SCI文献检索 > JOURNAL OF BACTERIOLOGY期刊下所有文献 > Oxygen-insensitive nitroreductases: analysis of the roles of nfsA and nfsB in development of resistance to 5-nitrofuran derivatives in Escherichia coli.

Oxygen-insensitive nitroreductases: analysis of the roles of nfsA and nfsB in development of resistance to 5-nitrofuran derivatives in Escherichia coli.

Abstract：

:Nitroheterocyclic and nitroaromatic compounds constitute an enormous range of chemicals whose potent biological activity has significant human health and environmental implications. The biological activity of nitro-substituted compounds is derived from reductive metabolism of the nitro moiety, a process catalyzed by a variety of nitroreductase activities. Resistance of bacteria to nitro-substituted compounds is believed to result primarily from mutations in genes encoding oxygen-insensitive nitroreductases. We have characterized the nfsA and nfsB genes of a large number of nitrofuran-resistant mutants of Escherichia coli and have correlated mutation with cell extract nitroreductase activity. Our studies demonstrate that first-step resistance to furazolidone or nitrofurazone results from an nfsA mutation, while the increased resistance associated with second-step mutants is a consequence of an nfsB mutation. Inferences made from mutation about the structure-function relationships of NfsA and NfsB are discussed, especially with regard to the identification of flavin mononucleotide binding sites. We show that expression of plasmid-carried nfsA and nfsB genes in resistant mutants restores sensitivity to nitrofurans. Among the 20 first-step and 53 second-step mutants isolated in this study, 65 and 49%, respectively, contained insertion sequence elements in nfsA and nfsB. IS1 integrated in both genes, while IS30 and IS186 were found only in nfsA and IS2 and IS5 were observed only in nfsB. Insertion hot spots for IS30 and IS186 are indicated in nfsA, and a hot spot for IS5 insertion is evident in nfsB. We discuss potential regional and sequence-specific determinants for insertion sequence element integration in nfsA and nfsB.

journal_name

J Bacteriol

journal_title

Journal of bacteriology

authors

Whiteway J,Koziarz P,Veall J,Sandhu N,Kumar P,Hoecher B,Lambert IB

doi

10.1128/JB.180.21.5529-5539.1998

subject

Has Abstract

pub_date

1998-11-01 00:00:00

pages

5529-39

issue

eissn

0021-9193

issn

1098-5530

journal_volume

180

pub_type

杂志文章

在线工具

Oxygen-insensitive nitroreductases: analysis of the roles of nfsA and nfsB in development of resistance to 5-nitrofuran derivatives in Escherichia coli.