Crystal structures of ethanolamine ammonia-lyase complexed with coenzyme B12 analogs and substrates.

N-terminal truncation of the Escherichia coli ethanolamine ammonia-lyase beta-subunit does not affect the catalytic properties of the enzyme (Akita, K., Hieda, N., Baba, N.

Expression, crystallization and preliminary X-ray crystallographic study of ethanolamine ammonia-lyase from Escherichia coli.

Ethanolamine ammonia-lyase (EAL) catalyzes the adenosylcobalamin-dependent conversion of ethanolamine to acetaldehyde and ammonia. The wild-type enzyme shows a very low solubility. N-terminal truncation of the Escherichia coli EAL beta-subunit dramatically increases the solubility of the enzyme without altering its catalytic properties.

Purification and some properties of wild-type and N-terminal-truncated ethanolamine ammonia-lyase of Escherichia coli.

The methods of homologous high-level expression and simple large-scale purification for coenzyme B(12)-dependent ethanolamine ammonia-lyase of Escherichia coli were developed. The eutB and eutC genes in the eut operon encoded the large and small subunits of the enzyme, respectively. The enzyme existed as the heterododecamer alpha(6)beta(6).

Mechanism-based inactivation of coenzyme B12-dependent diol dehydratase by 3-unsaturated 1,2-diols and thioglycerol.

The reactions of diol dehydratase with 3-unsaturated 1,2-diols and thioglycerol were investigated. Holodiol dehydratase underwent rapid and irreversible inactivation by either 3-butene-1,2-diol, 3-butyne-1,2-diol or thioglycerol without catalytic turnovers. In the inactivation, the Co-C bond of adenosylcobalamin underwent irreversible cleavage forming unidentified radicals and cob(II)alamin that resisted oxidation even in the presence of oxygen.

Histidine-alpha143 assists 1,2-hydroxyl group migration and protects radical intermediates in coenzyme B12-dependent diol dehydratase.

Diol dehydratase of Klebsiella oxytoca contains an essential histidine residue. Its X-ray structure revealed that the migrating hydroxyl group on C2 of substrate is hydrogen-bonded to Hisalpha143. Mutant enzymes in which Hisalpha143 was mutated to another amino acid residue were expressed in Escherichia coli, purified, and examined for enzymatic activity.

Crystallization and preliminary X-ray analysis of molecular chaperone-like diol dehydratase-reactivating factor in ADP-bound and nucleotide-free forms.

Adenosylcobalamin (coenzyme B12) dependent diol dehydratase (EC 4.2.1.

Release of a damaged cofactor from a coenzyme B12-dependent enzyme: X-ray structures of diol dehydratase-reactivating factor.

The crystal structures of ADP bound and nucleotide-free forms of molecular chaperone-like diol dehydratase-reactivating factor (DDR) were determined at 2.0 and 3.0 A, respectively.