Structural highlights
Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedBacteriophage T4 deoxycytidylate hydroxymethylase (EC 2.1.2.8), a homodimer of 246-residue subunits, catalyzes hydroxymethylation of the cytosine base in deoxycytidylate (dCMP) to produce 5-hydroxymethyl-dCMP. It forms part of a phage DNA protection system and appears to function in vivo as a component of a multienzyme complex called deoxyribonucleoside triphosphate (dNTP) synthetase. We have determined its crystal structure in the presence of the substrate dCMP at 1.6 A resolution. The structure reveals a subunit fold and a dimerization pattern in common with thymidylate synthases, despite low (approximately 20%) sequence identity. Among the residues that form the dCMP binding site, those interacting with the sugar and phosphate are arranged in a configuration similar to the deoxyuridylate binding site of thymidylate synthases. However, the residues interacting directly or indirectly with the cytosine base show a more divergent structure and the presumed folate cofactor binding site is more open. Our structure reveals a water molecule properly positioned near C-6 of cytosine to add to the C-7 methylene intermediate during the last step of hydroxymethylation. On the basis of sequence comparison and crystal packing analysis, a hypothetical model for the interaction between T4 deoxycytidylate hydroxymethylase and T4 thymidylate synthase in the dNTP-synthesizing complex has been built. Crystal structure of deoxycytidylate hydroxymethylase from bacteriophage T4, a component of the deoxyribonucleoside triphosphate-synthesizing complex.,Song HK, Sohn SH, Suh SW EMBO J. 1999 Mar 1;18(5):1104-13. PMID:10064578[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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