A cysteine desulphurase gene from the cellulolytic rumen anaerobe Ruminococcus flavefaciens

A gene whose predicted product shows 40-50% sequence identity with the products of nifS genes from nitrogen-fixing bacteria was found downstream from a cellulase gene in a DNA fragment from the cellulolytic rumen anaerobe, Ruminococus flavefaciens 17. The R. flavefaciens gene product released sulphur from L-cysteine when expressed in Escherichia coli, indicating that the R. flavefaciens NifS enzyme may play a role in sulphuration, perhaps, as in nitrogen-fixing bacteria, supplying sulphur to FeS proteins. Sequences hybridising with the R flavefaciens 17 nifS-like gene were also detected in R flavefaciens 007 and in R albus SY3. (C) 1998 Elsevier Science B.V. All rights reserved.