Cytidine deaminase (EC 22.214.171.124) (cytidine aminohydrolase) catalyzes the
hydrolysis of cytidine into uridine and ammonia while deoxycytidylate
deaminase (EC 126.96.36.199) (dCMP deaminase) hydrolyzes dCMP into dUMP. Both
enzymes are known to bind zinc and to require it for their catalytic activity
[1,2]. These two enzymes do not share any sequence similarity with the
exception of a region that contains three conserved histidine and cysteine
residues which are thought to be involved in the binding of the catalytic zinc
Such a region is also found in other proteins [3,4]:
Yeast cytosine deaminase (EC 188.8.131.52) (gene FCY1) which transforms cytosine
Mammalian apolipoprotein B mRNA editing protein, responsible for the
postranscriptional editing of a CAA codon into a UAA (stop) codon in the
Riboflavin biosynthesis protein ribG, which converts 2,5-diamino-6-
(ribosylamino)-4(3H)-pyrimidinone 5'-phosphate into 5-amino-6-
Bacillus cereus blasticidin-S deaminase (EC 184.108.40.206), which catalyzes the
deamination of the cytosine moiety of the antibiotics blasticidin S,
cytomycin and acetylblasticidin S.
Bacillus subtilis protein comEB. This protein is required for the binding
and uptake of transforming DNA.
Bacillus subtilis hypothetical protein yaaJ.
Escherichia coli hypothetical protein yfhC.
Yeast hypothetical protein YJL035c.
We have derived a signature pattern for this zinc-binding region.
May 2004 / Text revised.
PROSITE method (with tools and information) covered by this documentation:
Yang C., Carlow D., Wolfenden R., Short S.A.
Cloning and nucleotide sequence of the Escherichia coli cytidine deaminase (ccd) gene.
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