title: The fluorinase, the chlorinase and the duf-62 enzymes.
abstract: The fluorinase from Streptomyces cattleya and chlorinase from Salinispora tropica have a commonality in that they mediate nucleophilic reactions of their respective halide ions to the C-5' carbon of S-adenosyl-L-methionine (SAM). These enzyme reactions fall into the relatively small group of S(N)2 substitution reactions found in enzymology. These enzymes have some homology to a larger class of proteins expressed by the duf-62 gene, of which around 200 representatives have been sequenced and deposited in databases. The duf-62 genes express a protein which mediates a hydrolytic cleavage of SAM to generate adenosine and L-methionine. Superficially this enzyme operates very similarly to the halogenases in that water/hydroxide replaces the halide ion. However structural examination of the duf-62 gene product reveals a very different organisation of the active site suggesting a novel mechanism for water activation.
authors.affiliation: University of St Andrews, School of Chemistry and Centre for Biomolecular Sciences, North Haugh, St Andrews, Fife KY16 9ST, UK. hd9@st-andrews.ac.uk
authors.forename: Hai
authors.initials: H
authors.lastname: Deng
authors.forename: David
authors.initials: D
authors.lastname: O'Hagan
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000737:chemistry* / Q000378:metabolism*; D020134:Catalytic Domain; D002713:Chlorine / Q000737:chemistry / Q000378:metabolism*; D005461:Fluorine / Q000737:chemistry / Q000378:metabolism*; D010088:Oxidoreductases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D005461:Fluorine; D002713:Chlorine; D010088:Oxidoreductases; D019883:Alkyl and Aryl Transferases