Johnson J L, Rajagopalan K V, Mukund S, Adams M W
Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710.
J Biol Chem. 1993 Mar 5;268(7):4848-52.
The hyperthermophilic Archaea represent some of the most ancient organisms on earth. A study of enzymatic cofactors in these organisms could provide basic information on the origins of related cofactors in man and other more recently evolved organisms. To this end, the nature of the tungsten cofactor in aldehyde ferredoxin oxidoreductases from Pyrococcus furiosus and ES-4 and in formaldehyde ferredoxin oxidoreductases from P. furiosus and Thermococcus litoralis has been investigated. All four proteins contain molybdopterin, previously characterized as the organic component of the molybdenum cofactor in a large number of molybdoenzymes. Molybdopterin was identified by conversion to the dicarboxamidomethyl derivative by alkylation of the vicinal sulfhydryl groups on the pterin side chain and by conversion to the oxidized fluorescent derivative, Form A. The pterin of the tungsten cofactor in the four enzymes was examined for the presence of appended GMP, CMP, AMP, or IMP previously observed in molybdenum cofactors of some molybdoenzymes. No evidence for the presence of a molybdopterin dinucleotide or other modified form of molybdopterin was obtained. These results further document the essential nature of molybdopterin for the function of molybdenum and tungsten enzymes in diverse life forms.
嗜热古菌代表了地球上一些最古老的生物。对这些生物中酶辅因子的研究可以提供有关人类和其他近期进化生物中相关辅因子起源的基本信息。为此，研究了来自激烈火球菌和ES-4的醛铁氧还蛋白氧化还原酶以及来自激烈火球菌和嗜热栖热菌的甲醛铁氧还蛋白氧化还原酶中钨辅因子的性质。所有这四种蛋白质都含有钼蝶呤，此前在大量钼酶中被表征为钼辅因子的有机成分。通过对蝶呤侧链上的邻位巯基进行烷基化将其转化为二羧酰胺甲基衍生物，并将其转化为氧化荧光衍生物A来鉴定钼蝶呤。检查了这四种酶中钨辅因子的蝶呤，以确定是否存在先前在一些钼酶的钼辅因子中观察到的附加GMP、CMP、AMP或IMP。没有获得存在钼蝶呤二核苷酸或其他修饰形式的钼蝶呤的证据。这些结果进一步证明了钼蝶呤对于不同生命形式中钼酶和钨酶功能的本质重要性。
