NADPH的晶体结构:铁氧还蛋白还原酶从固氮菌vinelandii。
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bloom普拉萨德克,责任N, Muhlberg AB,肖,荣格y,伯吉斯BK,结实的CD
NADPH的晶体结构:铁氧还蛋白还原酶从固氮菌vinelandii。
蛋白质科学。1998;12月7 (12):2541 - 9。
- PubMed ID
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9865948 (在PubMed]
- 文摘
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NADPH:铁氧还蛋白还原酶(AvFPR)是参与反应的氧化应激在固氮菌vinelandii。AvFPR的晶体结构被确定为2.0决议。的多肽折叠与其他六个氧化还原酶同源结构解决了包括大肠杆菌flavodoxin还原酶(EcFldR)和菠菜,和淡水藻类的一种铁氧还蛋白:辅酶ii +还原酶(FNR)。AvFPR EcFldR整体最同源。的结构是由氨基端six-stranded反平行的beta-barrel域,结合时尚,c端five-stranded平行β褶板域,结合NADPH /辅酶ii +和核苷酸结合古典褶皱。两个域关联形成深裂NADPH和时尚结合位点是并列的。显示序列结构守恒的图案在该地区周围的两个二核苷酸结合位点,这是同源酶的特征。AvFPR的折叠构象的时尚是类似于EcFldR由于叠加Phe255腺嘌呤环上的时尚,但它不同于FNR酶,而缺乏相应的芳香残渣。AvFPR显示三个独特的结构特性的环境约束潮流。两个特性可能影响时尚的还原率:没有异咯嗪环的芳香渣堆放NADPH结合位点; and the interaction of a carbonyl group with N10 of the flavin. Both of these features are due to the substitution of a conserved C-terminal tyrosine residue with alanine (Ala254) in AvFPR. An additional unique feature may affect the interaction of AvFPR with its redox partner ferredoxin I (FdI). This is the extension of the C-terminus by three residues relative to EcFldR and by four residues relative to FNR. The C-terminal residue, Lys258, interacts with the AMP phosphate of FAD. Consequently, both phosphate groups are paired with a basic group due to the simultaneous interaction of the FMN phosphate with Arg51 in a conserved FAD binding motif. The fourth feature, common to homologous oxidoreductases, is a concentration of 10 basic residues on the face of the protein surrounding the active site, in addition to Arg51 and Lys258.