1kxz
From Proteopedia
MT0146, the Precorrin-6y methyltransferase (CbiT) homolog from M. Thermoautotrophicum, P1 spacegroup
Structural highlights
FunctionCBIT_METTH Catalyzes the methylation of C-15 in cobalt-precorrin-6B followed by the decarboxylation of C-12 to form cobalt-precorrin-7 (Probable).[1] 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 PubMedThe CbiT and CbiE enzymes participate in the biosynthesis of vitamin B12. They are fused together in some organisms to form a protein called CobL, which catalyzes two methylations and one decarboxylation on a precorrin intermediate. Because CbiE has sequence homology to canonical precorrin methyltransferases, CbiT was hypothesized to catalyze the decarboxylation. We herein present the crystal structure of MT0146, the CbiT homolog from Methanobacterium thermoautotrophicum. The protein shows structural similarity to Rossmann-like S-adenosyl-methionine-dependent methyltransferases, and our 1.9 A cocrystal structure shows that it binds S-adenosyl-methionine in standard geometry near a binding pocket that could accommodate a precorrin substrate. Therefore, MT0146/CbiT probably functions as a precorrin methyltransferase and represents the first enzyme identified with this activity that does not have the canonical precorrin methyltransferase fold. The crystal structure of MT0146/CbiT suggests that the putative precorrin-8w decarboxylase is a methyltransferase.,Keller JP, Smith PM, Benach J, Christendat D, deTitta GT, Hunt JF Structure. 2002 Nov;10(11):1475-87. PMID:12429089[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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