1L3I

MT0146, THE PRECORRIN-6Y METHYLTRANSFERASE (CBIT) HOMOLOG FROM M. THERMOAUTOTROPHICUM, ADOHCY BINARY COMPLEX

Summary for 1L3I

• Entry DOI: 10.2210/pdb1l3i/pdb
• Related: 1f38 1kxz 1l3b 1l3c
• Descriptor: Precorrin-6y methyltransferase/putative decarboxylase, S-ADENOSYL-L-HOMOCYSTEINE (3 entities in total)
• Functional Keywords: structural genomics, beta barrel, rossmann fold, tetramer, methyltransferase, decarboxylase, structure-based function assignment, transferase, lyase
• Biological source: Methanothermobacter thermautotrophicus
• Total number of polymer chains: 6
• Total formula weight: 128979.25

Authors

Keller, J.P.,Smith, P.M.,Benach, J.,Christendat, D.,deTitta, G.,Hunt, J.F. (deposition date: 2002-02-27, release date: 2002-11-27, Last modification date: 2023-11-15)

Primary citation

Keller, J.P.,Smith, P.M.,Benach, J.,Christendat, D.,deTitta, G.,Hunt, J.F.
The Crystal Structure of Mt0146/CbiT Suggests that the Putative Precorrin-8W Decarboxylase is a Methyltransferase
Structure, 10:1475-1487, 2002

PubMed Abstract: The 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.

PubMed: 12429089
DOI: 10.1016/S0969-2126(02)00876-6

Experimental method

X-RAY DIFFRACTION (1.95 Å)