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


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 Å, c = 221.07 Å. Diffraction images were processed to a resolution of 3.0 Å. The data collected so far indicate the approximate molecular boundaries and a partial main-chain trace of the enzyme.

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Ozawa, Y. , Umena, Y. , Imai, T. and Morimoto, Y. (2015) Subunit Arrangement of a 2-Ketoisovalerate Ferredoxin Oxidoreductase from Thermococcus profundus Revealed by a Low Resolution X-Ray Analysis. Advances in Enzyme Research, 3, 75-80. doi: 10.4236/aer.2015.33008.

Conflicts of Interest

The authors declare no conflicts of interest.


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