RESUMEN
Purified malate dehydrogenase (MDH) of Streptomyces aureofaciens was crystallized either in the absence or in the presence of NADH or NADPH coenzymes by hanging-drop vapour-diffusion method. An X-ray study has shown, that MDH crystals belong to space group C222(1) with unit-cell parameters a = 53.2 A, b = 104.6 A, c = 520.0 A, alpha = beta = gamma = 90( degrees ), MDH-NADH crystals to space group C2 with unit-cell parameters a = 51.5 A, b = 51.5 A, c = 256 A, alpha = beta = gamma = 90( degrees ), and MDH-NADPH crystals to space group C222(1) with unit-cell parameters a = 72, A b = 72 A, c = 520 A, alpha = beta = gamma = 90( degrees ). The crystal of native MDH diffracted to 2.1 A resolution.
Asunto(s)
Malato Deshidrogenasa/química , Malato Deshidrogenasa/metabolismo , Streptomyces aureofaciens/enzimología , Cristalización , Cristalografía por Rayos X , Malato Deshidrogenasa/genética , Malato Deshidrogenasa/aislamiento & purificación , NADP/química , NADP/metabolismo , Streptomyces aureofaciens/genéticaRESUMEN
Thioredoxins are ubiquitous proteins that serve as reducing agents and general protein disulfide reductases. In turn, they are reduced by electrons obtained from the NADPH-containing thioredoxin reductase. Thioredoxins have been isolated and characterized from a large number of organisms. The Gram-positive bacterium Streptomyces coelicolor contains three thioredoxins that are involved in unknown biological processes. trxA from S. coelicolor was cloned and expressed in Escherichia coli and the protein purified and crystallized using the hanging-drop method of vapour diffusion. The crystal structure of thioredoxin A has been determined at 1.5 A resolution using a synchrotron-radiation source. The protein reveals a thioredoxin-like fold with a typical CXXC active site. The crystal exhibits the symmetry of space group P2(1)2(1)2, with unit-cell parameters a = 43.6, b = 71.8, c = 33.2 A.
Asunto(s)
Streptomyces coelicolor/química , Tiorredoxinas/química , Secuencia de Aminoácidos , Proteínas Bacterianas/química , Secuencia de Bases , Sitios de Unión , Clonación Molecular , Secuencia Conservada , Cristalografía por Rayos X , Cartilla de ADN , Escherichia coli/química , Modelos Moleculares , Estructura Secundaria de Proteína , Alineación de Secuencia , SincrotronesRESUMEN
The mononuclear title complex, [Co(C(6)H(6)NO(6))(C(2)H(8)N(2))].3H(2)O, contains an octahedrally coordinated Co(III) atom. The N-(carboxymethyl)aspartate moiety is coordinated as a tetradentate ligand, providing an OONO-donor set and forming two trans five-membered chelate rings and one six-membered chelate ring. A seven-membered chelate ring is also formed, which consists of part of the six-membered chelate ring and part of one of the five-membered chelate rings. The crystal structure of the complex is stabilized by hydrogen bonds with three water molecules.