PROSITE documentation PDOC00702

Cytidine and deoxycytidylate deaminases zinc-binding region signature


Cytidine deaminase (EC (cytidine aminohydrolase) catalyzes the hydrolysis of cytidine into uridine and ammonia while deoxycytidylate deaminase (EC (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 ion.

Such a region is also found in other proteins [3,4]:

  • Yeast cytosine deaminase (EC (gene FCY1) which transforms cytosine into uracil.
  • Mammalian apolipoprotein B mRNA editing protein, responsible for the postranscriptional editing of a CAA codon into a UAA (stop) codon in the APOB mRNA.
  • Riboflavin biosynthesis protein ribG, which converts 2,5-diamino-6- (ribosylamino)-4(3H)-pyrimidinone 5'-phosphate into 5-amino-6- (ribosylamino)-2,4(1H,3H)-pyrimidinedione 5'-phosphate.
  • Bacillus cereus blasticidin-S deaminase (EC, 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.

Last update:

May 2004 / Text revised.

Technical section

PROSITE method (with tools and information) covered by this documentation:

CYT_DCMP_DEAMINASES, PS00903; Cytidine and deoxycytidylate deaminases zinc-binding region signature  (PATTERN)


1AuthorsYang C., Carlow D., Wolfenden R., Short S.A.
TitleCloning and nucleotide sequence of the Escherichia coli cytidine deaminase (ccd) gene.
SourceBiochemistry 31:4168-4174(1992).
PubMed ID1567863

2AuthorsMoore J.T., Silversmith R.E., Maley G.F., Maley F.
TitleT4-phage deoxycytidylate deaminase is a metalloprotein containing two zinc atoms per subunit.
SourceJ. Biol. Chem. 268:2288-2291(1993).
PubMed ID8428902

3AuthorsReizer J., Buskirk S., Bairoch A., Reizer A., Saier M.H. Jr.
TitleA novel zinc-binding motif found in two ubiquitous deaminase families.
SourceProtein Sci. 3:853-856(1994).
PubMed ID8061614

4AuthorsBhattacharya S., Navaratnam N., Morrison J.R., Scott J., Taylor W.R.
TitleCytosine nucleoside/nucleotide deaminases and apolipoprotein B mRNA editing.
SourceTrends Biochem. Sci. 19:105-106(1994).
PubMed ID8203015

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