Cloned (Comment) | Organism |
---|---|
N-terminal His6-tagged beta subunit lacking residues Lysbeta4-Cysbeta43 | Escherichia coli |
Crystallization (Comment) | Organism |
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N-terminal His6-tagged beta subunit lacking residues Lysbeta4-Cysbeta43, in complex with cyanocobalamin and in complex with cyanocobalamin or adeninylpentylcobalamin and substrates. The enzyme exists as a trimer of the (alphabeta)2 dimer. The active site is in the (beta/alpha)8 barrel of the-subunit, the beta-subunit covers the lower part of the cobalamin that is bound in the interface of the alpha- and beta-subunits. The structure complexed with adeninylpentylcobalamin reveals the presence of an adenine ring-binding pocket in the enzyme that accommodates the adenine moiety through a hydrogen bond network. The substrate is bound by six hydrogen bonds with active-site residues. Arg160 contributes to substrate binding most likely by hydrogen bonding with the O1 atom. Marked angular strains and tensile forces induced by tight enzyme-coenzyme interactions are responsible for breaking the coenzyme-Co-C bond. A major structural change upon substrate binding is not observed with this particular enzyme. Glu287, one of the substrate-binding residues, has a direct contact with the ribose group of the modeled adenosylcobalamin, which may contribute to the substrate-induced additional labilization of the Co-C bond | Escherichia coli |
Organism | UniProt | Comment | Textmining |
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Escherichia coli | P19636 | - |
- |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
adenosylcobalamin | marked angular strains and tensile forces induced by tight enzyme-coenzyme interactions are responsible for breaking the coenzyme-Co-C bond. A major structural change upon substrate binding is not observed with this particular enzyme. Glu287, one of the substrate-binding residues, has a direct contact with the ribose group of the modeled adenosylcobalamin, which may contribute to the substrate-induced additional labilization of the Co-C bond | Escherichia coli |