A nitrogen-fixation gene (nifC) in Clostridium pasteurianum with sequence similarity to chlJ of Escherichia coli.
The molybdenum-containing nitrogenase contains an iron-molybdenum cofactor, whose synthesis involves at least six nif genes. Genes corresponding to nifE, N, B, and V occur in proximity in Clostridium pasteurianum, with nifN-B occurring as one gene and with nifV omega and nifV alpha in place of nifV. Between nifN-B and nifV omega V alpha, we found a gene whose sequence is similar to chlJ of Escherichia coli. chlJ is part of the chlD locus, which is involved in Mo transport. C. pasteurianum actively accumulates Mo in a process coregulated with nitrogen fixation. We propose that nifC is involved in Mo transport. The expression of nifC may be coregulated with nitrogen fixation because of the presence of nif-distinctive promoter and upstream sequences preceding nifC-nifV omega-nifV alpha. NifC contains a region typical of integral membrane proteins. Our findings suggest the involvement of a membrane-located nif gene product in Mo transport in C. pasteurianum.
Department of Anaerobic Microbiology, Virginia Polytechnic Institute and State University, Blacksburg 24061.
S Z
SZ
Wang
J S
JS
Chen
J L
JL
Johnson
D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport; D003001:Cloning, Molecular; D003013:Clostridium / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D008982:Molybdenum / Q000378:metabolism*; D009586:Nitrogen Fixation / Q000235:genetics*; D009876:Operon; D011401:Promoter Regions, Genetic; D012045:Regulatory Sequences, Nucleic Acid
D008565:Membrane Proteins; D008982:Molybdenum