#1: ジャーナル: J.Biol.Chem. / 年: 2003 タイトル: Roles of Active Site and Novel K+ Ion-Binding Site Residues in Human Mitochondrial Branched-Chain Alpha-Ketoacid Decarboxylase/Dehydrogenase 著者: Wynn, R.M. / Ho, R. / Chuang, J.L. / Chuang, D.T.
THE BRANCHED-CHAIN ALPHA-KETO DEHYDROGENASE COMPLEX CATALYZES CONVERSION OF ALPHA-KETO ACIDS TO ...THE BRANCHED-CHAIN ALPHA-KETO DEHYDROGENASE COMPLEX CATALYZES CONVERSION OF ALPHA-KETO ACIDS TO ACYL-COA AND CO(2). CONTAINS MULTIPLE COPIES OF 3 ENZYMATIC COMPONENTS: BRANCHED-CHAIN ALPHA-KETO ACID DECARBOXYLASE (E1), LIPOAMIDE ACYLTRANSFERASE (E2) AND LIPOAMIDE DEHYDROGENASE (E3). REQUIRES THIAMINE PYROPHOSPHATE AS A COFACTOR AND EXISTS AS A HETERODIMER OF AN ALPHA AND A BETA CHAIN. ENGINEERED MUTATION HIS 334 ALA, CHAIN A
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実験情報
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実験
実験
手法: X線回折 / 使用した結晶の数: 1
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試料調製
結晶
マシュー密度: 2.5 Å3/Da / 溶媒含有率: 51 %
結晶化
温度: 293 K / 手法: 蒸気拡散法 / pH: 5.5 詳細: CRYSTALS WERE GROWN AT 20C VIA THE VAPOR DIFFUSION METHOD BY MIXING EQUAL AMOUNTS OF PROTEIN (20-25 MG/ML IN 50 MM HEPES/NAOH, PH 7.5, 250 MM KCL, 0.5 MM PMSF, 1 MM BENZAMIDINE AND 5% (V/V) ...詳細: CRYSTALS WERE GROWN AT 20C VIA THE VAPOR DIFFUSION METHOD BY MIXING EQUAL AMOUNTS OF PROTEIN (20-25 MG/ML IN 50 MM HEPES/NAOH, PH 7.5, 250 MM KCL, 0.5 MM PMSF, 1 MM BENZAMIDINE AND 5% (V/V) GLYCEROL) WITH WELL SOLUTION (1.4-1.6 M AMMONIUM SULFATE, 0.1 M NA-CITRATE PH 5.8, 20 MM B-MERCAPTOETHANOL). SERIALLY DILUTED CRUSHED CRYSTALS WERE USED FOR MICRO-SEEDING ONE DAY AFTER THE DROPS WERE SET UP. CRYSTALS APPEARED ONE DAY AFTER SEEDING AND GREW TO A MAXIMUM SIZE OF 120 X 800 UM WITHIN 10 DAYS. CRYSTALS WERE STABILIZED FOR 12 HOURS BY TRANSFER TO FRESH WELL SOLUTION. THEY WERE THEN CRYO-PROTECTED BY STEP-WISE TRANSFER INTO CRYO-BUFFER CONTAINING 1.6 M AMMONIUM SULFATE, 50 MM HEPES, PH 7.5, 100 MM NA-CITRATE, PH 5.8, 100 MM KCL, 50 MM DTT AND UP TO 20% (V/V) GLYCEROL. IT WAS FOUND THAT MN2+ IONS COULD REPLACE THE MG2+ REQUIRED FOR THE BINDING OF THDP TO THE ENZYME.
解像度: 1.9→23.79 Å / Rfactor Rfree error: 0.006 / Data cutoff high absF: 836405.6 / Isotropic thermal model: RESTRAINED / 交差検証法: THROUGHOUT / σ(F): 0 詳細: THE FOLLOWING REGION HAD VERY POOR ELECTRON DENSITY: ALPHA CHAIN RESIDUES 4 THROUGH 14. SIDE CHAINS OF THE FOLLOWING RESIDUES DID HAVE POORLY DEFINED ELECTRON DENSITY AND WERE MODELLED ...詳細: THE FOLLOWING REGION HAD VERY POOR ELECTRON DENSITY: ALPHA CHAIN RESIDUES 4 THROUGH 14. SIDE CHAINS OF THE FOLLOWING RESIDUES DID HAVE POORLY DEFINED ELECTRON DENSITY AND WERE MODELLED STEREOCHEMICALLY: ALPHA CHAIN: K19, E55, Y286, R287, D313, E347, K400 BETA CHAIN: Q7