RRC ID 17419
Author Yoshida Y, Ito S, Kamo M, Kezuka Y, Tamura H, Kunimatsu K, Kato H.
Title Production of hydrogen sulfide by two enzymes associated with biosynthesis of homocysteine and lanthionine in Fusobacterium nucleatum subsp. nucleatum ATCC 25586.
Journal Microbiology (Reading)
Abstract Fusobacterium nucleatum produces a large amount of the toxic metabolite hydrogen sulfide in the oral cavity. Here, we report the molecular basis of F. nucleatum H(2)S production, which is associated with two different enzymes: the previously reported Cdl (Fn1220) and the newly identified Lcd (Fn0625). SDS-PAGE analysis with activity staining revealed that crude enzyme extracts from F. nucleatum ATCC 25586 contained three major H(2)S-producing proteins. Two of the proteins with low molecular masses migrated similarly to purified Fn0625 and Fn1220. Their kinetic values suggested that Fn0625 had a lower enzymic capacity to produce H(2)S from L-cysteine (approximately 30%) than Fn1220. The Fn0625 protein degraded a variety of substrates containing betaC-S linkages to produce ammonia, pyruvate and sulfur-containing products. Unlike Fn0625, Fn1220 produced neither pyruvate nor ammonia from L-cysteine. Reversed-phase HPLC separation and mass spectrometry showed that incubation of L-cysteine with Fn1220 produced H(2)S and an uncommon amino acid, lanthionine, which is a natural constituent of the peptidoglycans of F. nucleatum ATCC 25586. In contrast, most of the sulfur-containing substrates tested, except L-cysteine, were not used by Fn1220. Real-time PCR analysis demonstrated that the fn1220 gene showed several-fold higher expression than fn0625 and housekeeping genes in exponential-phase cultures of F. nucleatum. Thus, we conclude that Fn0625 and Fn1220 produce H(2)S in distinct manners: Fn0625 carries out beta-elimination of L-cysteine to produce H(2)S, pyruvate and ammonia, whereas Fn1220 catalyses the beta-replacement of L-cysteine to produce H(2)S and lanthionine, the latter of which may be used for peptidoglycan formation in F. nucleatum.
Volume 156(Pt 7)
Pages 2260-2269
Published 2010-7-1
DOI 10.1099/mic.0.039180-0
PMID 20413556
MeSH Alanine / analogs & derivatives* Alanine / biosynthesis Ammonia / metabolism Aspartate Aminotransferases / chemistry Aspartate Aminotransferases / genetics Aspartate Aminotransferases / metabolism* Bacterial Proteins / chemistry Bacterial Proteins / genetics Bacterial Proteins / metabolism* Cysteine Synthase / chemistry Cysteine Synthase / genetics Cysteine Synthase / metabolism* Fusobacterium nucleatum / chemistry Fusobacterium nucleatum / enzymology Fusobacterium nucleatum / genetics Fusobacterium nucleatum / metabolism* Homocysteine / biosynthesis* Hydrogen Sulfide / metabolism* Kinetics Pyruvic Acid / metabolism Substrate Specificity Sulfides
IF 2.138
Times Cited 23
General Microbes JCM 8532 JCM 12990