HMM Summary Page: TIGR01706

Functionperiplasmic nitrate reductase, large subunit
Gene SymbolnapA
Trusted Cutoff930.55
Domain Trusted Cutoff930.55
Noise Cutoff472.50
Domain Noise Cutoff472.50
Isology Typeequivalog
EC Number1.7.99.4
HMM Length830
Mainrole CategoryEnergy metabolism
Subrole CategoryAerobic
Gene Ontology TermGO:0008940: nitrate reductase activity molecular_function
GO:0009325: nitrate reductase complex cellular_component
GO:0042126: nitrate metabolic process biological_process
GO:0055114: oxidation-reduction process biological_process
AuthorSelengut J
Entry DateSep 26 2002 11:05AM
Last ModifiedFeb 14 2011 3:27PM
CommentThis model represents the large subunit of a family of nitrate reductases found in proteobacteria which are localized to the periplasm. This subunit binds molybdopterin and contains a twin-arginine motif at the N-terminus. The protein associates with NapB, a soluble heme-containing protein and NapC, a membrane-bound cytochrome c. The periplasmic nitrate reductases are not involved in the assimilation of nitrogen, and are not directly involved in the formation of electrochemical gradients (i.e. respiration) either. Rather, the purpose of this enzyme is either dissimilatory (i.e. to dispose of excess reductive equivalents) or indirectly respiratory by virtue of the consumption of electrons derived from NADH via the proton translocating NADH dehydrogenase [4]. The enzymes from Alicagenes eutrophus [1] and Paracoccus pantotrophus [2] have been characterized. In E. coli [3] (as well as other organisms) this gene is part of a large nitrate reduction operon (napFDAGHBC).
ReferencesRN [1] RM PMID: 8376334 RT Structure and function of a periplasmic nitrate reductase in Alcaligenes eutrophus H16 RA RA Siddiqui, U Warnecke-Eberz, A Hengsberger, B Schneider, S Kostka and B Friedrich RL J. Bacteriol., 09 1993, 5867-5876, Vol 175, No. 18 RN [2] RM PMID: 7639719 RT The napEDABC gene cluster encoding the periplasmic nitrate reductase system of Thiosphaera pantotropha. RA Berks B.C., Richardson D.J., Reilly A., Willis A.C., Ferguson S.J.; RL Biochem. J. 309:983-992(1995). RN [3] RM PMID: 11844760 RT Periplasmic nitrate reductase (NapABC enzyme) supports anaerobic respiration by Escherichia coli K-12. RA Stewart V, Lu Y, Darwin AJ. RL J Bacteriol 2002 Mar;184(5):1314-23 RN [4] RM PMID: 9720883 RT Definition and distinction between assimilatory, dissimilatory and respiratory pathways. RA Moreno-Vivian C, Ferguson SJ. RL Mol Microbiol 1998 Jul;29(2):664-6 DR HAMAP; MF_01630; 89 of 93
Genome PropertyGenProp0200: periplasmic nitrate reductase (HMM)