HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Fujinaga, K. Articles by Okabe, A. Search for Related Content PubMed PubMed Citation Articles by Fujinaga, K. Articles by Okabe, A. Agricola Articles by Fujinaga, K. Articles by Okabe, A.

Analysis of genes involved in nitrate reduction in Clostridium perfringens

Department of Microbiology, Faculty of Medicine, Kagawa Medical University, Miki-cho, Kita-gun, Kagawa 761-0793, Japan ¹

Author for correspondence: Akinobu Okabe. Tel: +81 87 891 2129. Fax: +81 87 891 2129. e-mail: microbio{at}kms.ac.jp

We have conducted the genetic analysis of fermentative nitrate reduction in Clostridium perfringens, a strict anaerobic bacterium. Nitrate reductase (NarA) was purified from the cytoplasmic fraction of the organism. Using a degenerate primer designed from its N- terminal amino acid sequence, a 9·5 kb fragment containing seven ORFs was cloned. The molecular mass and N-terminal amino acid sequence predicted from the nucleotide sequence of ORF 4 coincided with those determined for the purified NarA, indicating that ORF 4 corresponds to a narA gene. ORFs 5 and 6 encode a 15·4 kDa ferredoxin-like protein containing four iron–sulfur clusters and a 45 kDa protein homologous to NADH oxidase, respectively. Analyses involving primer extension and Northern blotting revealed that these three ORFs are transcribed as a polycistronic message. The ORF 5- and ORF 6-encoded proteins were shown by immunoblotting to be synthesized by cells grown in the presence of nitrate. Thus, these two proteins are likely to function as electron-transfer components in nitrate reduction in C. perfringens. The 9·5 kb fragment and a downstream region of 6·1 kb do not contain any genes involved in nitrate uptake or nitrite reduction. Instead, all 5 ORFs downstream of ORF 6 are homologous to genes reported for molybdopterin biosynthesis, unlike the genomic organization already determined for the respiratory and assimilatory nitrate-reduction systems. The evolutionary relationships between these two nitrate- reduction systems and the fermentative one based on the results of comparative genetic analysis are discussed.

Keywords: Clostridium perfringens, nitrate reductase, molybdopterin guanine dinucleotide, ferredoxin-like protein, NADH oxidase

Abbreviations: NaR, nitrate reductase; NarA, nitrate reductase of Clostridium perfringens; NiR, nitrite reductase; Mo-MGD, a molybdenum–molybdopterin guanine dinucleotide complex

The GenBank accession number for the sequence reported in this paper is AB017192.

This article has been cited by other articles:

				K. Takasaki, H. Shoun, M. Yamaguchi, K. Takeo, A. Nakamura, T. Hoshino, and N. Takaya Fungal Ammonia Fermentation, a Novel Metabolic Mechanism That Couples the Dissimilatory and Assimilatory Pathways of Both Nitrate and Ethanol: ROLE OF ACETYL CoA SYNTHETASE IN ANAEROBIC ATP SYNTHESIS J. Biol. Chem., March 26, 2004; 279(13): 12414 - 12420. [Abstract] [Full Text] [PDF]

				M. Kaji, O. Matsushita, E. Tamai, S. Miyata, Y. Taniguchi, S. Shimamoto, S. Katayama, S. Morita, and A. Okabe A novel type of DNA curvature present in a Clostridium perfringens ferredoxin gene: characterization and role in gene expression Microbiology, November 1, 2003; 149(11): 3083 - 3091. [Abstract] [Full Text] [PDF]