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- ********************************************************
- * Prokaryotic molybdopterin oxidoreductases signatures *
- ********************************************************
-
- A number of different prokaryotic oxidoreductases that require and bind a
- molybdopterin cofactor have been shown [1,2] to share a number of regions of
- sequence similarity. These enzymes are:
-
- - Escherichia coli respiratory nitrate reductase (EC 1.7.99.4). This enzyme
- complex allows the bacteria to use nitrate as an electron acceptor during
- anaerobic growth. The enzyme is composed of three different chains: alpha,
- beta and gamma. The alpha chain (gene narG) is the molybdopterin-binding
- subunit. Escherichia coli encodes for a second, closely related, nitrate
- reductase complex which also contains a molybdopterin-binding alpha chain
- (gene narZ).
- - Escherichia coli anaerobic dimethyl sulfoxide reductase (DMSO reductase).
- DMSO reductase is the terminal reductase during anaerobic growth on various
- sulfoxide and N-oxide compounds. DMSO reductase is composed of three
- chains: A, B and C. The A chain (gene dmsA) binds molybdopterin.
- - Biotin sulfoxide reductase (gene bisC). This enzyme reduces a spontaneous
- oxidation product of biotin, BDS, back to biotin. It may serve as a
- scavenger, allowing the cell to use biotin sulfoxide as a biotin source.
- - Methanobacterium formicicum formate dehydrogenase (EC 1.2.1.2). The alpha
- chain (gene fdhA) of this dimeric enzyme binds a molybdopterin cofactor.
- - Escherichia coli formate dehydrogenases -H (gene fdhF), -N (gene fdnG) and
- -O (gene fdoG). These enzymes are responsible for the oxidation of formate
- to carbon dioxide. In addition to molybdopterin, the alpha (catalytic)
- subunit also contains an active site, selenocysteine.
- - Wolinella succinogenes polysulfide reductase chain. This enzyme is a
- component of the phosphorylative electron transport system with polysulfide
- as the terminal acceptor. It is composed of three chains: A, B and C. The
- A chain (gene psrA) binds molybdopterin [3].
- - Escherichia coli trimethylamine-N-oxide reductase (EC 1.6.6.9) (gene torA)
- [4].
-
- These proteins range from 715 amino acids (fdhF) to 1246 amino acids (narZ) in
- size.
-
- We derived three signature patterns for these enzymes. The first is based on a
- conserved region in the N-terminal section and contains two cysteine residues
- perhaps involved in binding the molydboterin cofactor. It should be noted
- that this region is not present in bisC. The second pattern is derived from a
- conserved region located in the central part of these enzymes.
-
- -Consensus pattern: [STN]-x-[CG]-x(2,3)-C-[STAG]-[GSV]-x-C-x-[LIVMFYW]-x-
- [LIVMA]-x(3,4)-[DN]
- -Sequences known to belong to this class detected by the pattern: ALL, except
- for bisC and torA.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Consensus pattern: [STA]-x-[STAC](2)-x(2)-[STA]-D-[LIVM](2)-L-P-x-[STAC](2)-
- x(2)-E
- -Sequences known to belong to this class detected by the pattern: ALL, except
- for fdnG and fdoG.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Consensus pattern: A-x(3)-[GT]-I-x-[DNQ]-x-[DEA]-x-[LIVM]-x-[LIVM]-x-[NS]-
- x(2)-[GS]-x(5)-A-x-[LIVM]-[ST]
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Last update: June 1994 / Text revised.
-
- [ 1] Wooton J.C., Nicolson R.E., Cock J.M., Walters D.E., Burke J.F.,
- Doyle W.A., Bray R.C.
- Biochim. Biophys. Acta 1057:157-185(1991).
- [ 2] Bilous P.T., Cole S.T., Anderson W.F., Weiner J.H.
- Mol. Microbiol. 2:785-795(1988).
- [ 3] Krafft T., Bokranz M., Klimmek O., Schroeder I., Fahrenholz F.,
- Kojro E., Kroeger A.
- Eur. J. Biochem. 206:503-510(1992).
- [ 4] Mejean V., Lobbi-Nivol C., Lepelletier M., Giordano G., Chippaux M.,
- Pascal M.-C.
- Mol. Microbiol. 11:1169-1179(1994).
-