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1b5e
From Proteopedia
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'''DCMP HYDROXYMETHYLASE FROM T4''' | '''DCMP HYDROXYMETHYLASE FROM T4''' | ||
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[[Category: Song, H K.]] | [[Category: Song, H K.]] | ||
[[Category: Suh, S W.]] | [[Category: Suh, S W.]] | ||
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| - | [[Category: | + | [[Category: Hydroxymethylase]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 11:05:38 2008'' | |
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Revision as of 08:05, 2 May 2008
DCMP HYDROXYMETHYLASE FROM T4
Overview
Bacteriophage 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.
About this Structure
1B5E is a Single protein structure of sequence from Enterobacteria phage t4. Full crystallographic information is available from OCA.
Reference
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 Page seeded by OCA on Fri May 2 11:05:38 2008
