1v9a
From Proteopedia
Crystal structure of Uroporphyrin-III C-methyl transferase from Thermus thermophilus complexed with S-adenyl homocysteine
Structural highlights
FunctionEvolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedUroporphyrinogen-III C-methyltransferase from Thermus thermophilus is a multifunctional protein responsible for two of the eight S-adenosyl-methionine-dependent methylations of the corrin ring during vitamin B(12) synthesis. The structure of this protein has been solved to 2.0 A resolution in both the apo and cofactor-bound form. The monomer consists of two domains, A and B, each consisting of a five-stranded beta-sheet and two or three alpha-helices, with the cofactor bound at the interface. The biological unit is the dimer found in the asymmetric unit. This dimer is related by a non-crystallographic twofold such that two B domains combine to form a long ten-stranded beta-sheet. When compared with solved related structures, this structure shows clear differences in the region involved in cofactor and substrate binding, affirming the role of several previously implicated residues and questioning others. The solved related structures are characterized by an exposed active site. The T. thermophilus structure has this site restricted by the interaction of a flexible loop structure with a highly conserved residue, suggesting a mechanistic role. This structure represents the ;closed' form of the protein. Structure of a closed-form uroporphyrinogen-III C-methyltransferase from Thermus thermophilus.,Rehse PH, Kitao T, Tahirov TH Acta Crystallogr D Biol Crystallogr. 2005 Jul;61(Pt 7):913-9. Epub 2005, Jun 24. PMID:15983414[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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