Subunit Arrangement of a 2-Ketoisovalerate Ferredoxin Oxidoreductase from Thermococcus profundus Revealed by a Low Resolution X-Ray Analysis  

作　　者：Yukiko Ozawa Yasufumi Umena Takeo Imai Yukio Morimoto 

机构地区：[1]Department of Life Science and Graduate School of Life Science, Rikkyo (St. Paul’s) University, Tokyo, Japan [2]Photosynthesis Research Center, Okayama University, Okayama, Japan [3]Research Reactor Institute, Kyoto University, Osaka, Japan

出　　处：《Advances in Enzyme Research》2015年第3期75-80,共6页酶研究进展（英文）

摘　　要：2-ketoisovalerate ferredoxin oxidoreductase (VOR) is a key enzyme in hyperthermophiles catalyzing the coenzyme A-dependent oxidative decarboxylation of aliphatic amino acid-derived 2-keto acids. The enzyme purified under anaerobic conditions from a hyperthermophilic archaeon, Thermococcus profundus, is a hetero-octamer (αβγδ)2 consisting of four different subunits, α = 45 kDa, β = 31 kDa, γ = 22 kDa and δ = 13 kDa, respectively, and it has three [4Fe-4S] clusters per αβγδ-protomer, similar to other ferredoxin oxidoreductases. In the present study, the native enzyme was purified from this strain and crystallized to give rod-like crystals that were suitable for X-ray diffraction experiments. The crystals belonged to space group P41212, with unit-cell parameters a = b = 136.20 ?, c = 221.07 ?. Diffraction images were processed to a resolution of 3.0 ?. The data collected so far indicate the approximate molecular boundaries and a partial main-chain trace of the enzyme.2-ketoisovalerate ferredoxin oxidoreductase (VOR) is a key enzyme in hyperthermophiles catalyzing the coenzyme A-dependent oxidative decarboxylation of aliphatic amino acid-derived 2-keto acids. The enzyme purified under anaerobic conditions from a hyperthermophilic archaeon, Thermococcus profundus, is a hetero-octamer (αβγδ)2 consisting of four different subunits, α = 45 kDa, β = 31 kDa, γ = 22 kDa and δ = 13 kDa, respectively, and it has three [4Fe-4S] clusters per αβγδ-protomer, similar to other ferredoxin oxidoreductases. In the present study, the native enzyme was purified from this strain and crystallized to give rod-like crystals that were suitable for X-ray diffraction experiments. The crystals belonged to space group P41212, with unit-cell parameters a = b = 136.20 ?, c = 221.07 ?. Diffraction images were processed to a resolution of 3.0 ?. The data collected so far indicate the approximate molecular boundaries and a partial main-chain trace of the enzyme.

关 键 词：OXIDOREDUCTASE X-Ray Analysis Iron-Sulfur Cluster 

分 类 号：R73[医药卫生—肿瘤]