Structures and functions of four anabolic 2-oxoacid oxidoreductases in Methanobacterium thermoautotrophicum.
Structures and functions of four anabolic 2-oxoacid oxidoreductases in Methanobacterium thermoautotrophicum.
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热自养甲烷杆菌中四种合成代谢 2-含氧酸氧化还原酶的结构和功能。
DOI：
10.1111/j.1432-1033.1997.00862.x
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
R. Hedderich
中科院分区：
文献类型：
--
作者：
A. Tersteegen;D. Linder;R. Thauer;R. Hedderich
Methanobacterium thermoautotrophicum (strain Marburg), which grows autotrophically on H2 and CO2, was found to contain 2-oxoisovalerate oxidoreductase (Vor) and indolepyruvate oxidoreductase (Ior) besides pyruvate oxidoreductase (Por) and 2-oxoglutarate oxidoreductase (Kor). So far, Vor and Ior have only been detected in peptide-utilizing hyperthermophilic Archaea. The four 2-oxoacid oxidoreductases were purified and characterized with respect to their subunit composition, N-terminal amino acid sequences, and catalytic properties. Por and Kor were composed of four different subunits, Vor was composed of three different subunits, and Ior of two different subunits. Comparisons of the N-terminal amino acid sequences revealed that the four enzymes are structurally related to each other and to the respective enzymes from Pyrococcus and Thermococcus sp. Vor from M. thermoautotrophicum differed from Vor from Pyrococcus furiosus in being composed of only three instead of four different subunits. Evidence is presented that in the autotrophic methanogen the four 2-oxoacid oxidoreductases have anabolic functions, Vor and Ior being involved in the biosynthesis of amino acids from fatty acids taken up from the growth medium, as shown by 14C-labelling studies.
