Crystallographic studies of V44 mutants of Clostridium pasteurianum rubredoxin: effects of side-chain size on reduction potential.
Crystallographic studies of V44 mutants of Clostridium pasteurianum rubredoxin: effects of side-chain size on reduction potential.
复制标题
巴氏梭菌红氧还蛋白 V44 突变体的晶体学研究：侧链大小对还原电位的影响。
DOI：
10.1002/prot.20243
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发表时间：
2004
期刊：
影响因子：
2.9
通讯作者：
Kang,Chulhee
中科院分区：
文献类型：
--
作者：
Park,IlYeong;Eidsness,MarlyK;Lin,I-Jin;Gebel,ErikaB;Youn,Buhyun;Harley,JillL;Machonkin,TimothyE;Frederick,RonnieO;Markley,JohnL;Smith,EugeneT;Ichiye,Toshiko;Kang,Chulhee
了解还原电位差异的结构起源对于了解各种电子转移蛋白如何调节其还原电位以及它们如何演变为不同的功能角色至关重要。在这里，为了增加这种理解，报告了几种在氧化还原位点附近发生变化的巴氏梭菌戊二酸Rubredoxin（Cp Rd）变体的高分辨率结构。[V44 L]的晶体结构（1.8 mm分辨率），[V44 A]（1.6毫米），[V44 G]（2.0 μ m）和[V44A，G45P]（1.5公里）Rd（均处于氧化态）表明，在残基44的侧链尺寸减小时，Fe和残基44的酰胺氮之间的距离逐渐减小;从亮氨酸到缬氨酸、丙氨酸或甘氨酸发生降低，并且伴随着它们的还原电位的逐渐增加。位置44处的Cp Rd突变还以大小依赖性方式改变残基44的酰胺氮与半胱氨酸42的硫之间的氢键距离。我们的结果表明，残基44是Rd降低潜力的重要决定因素，其方式取决于侧链大小。沿着43 - 44肽键的电偶极矩和44-42 NH-S型氢键，通过残基41的溶剂可及性的调节机制可能调节Rds的氧化还原反应。Proteins 2004.© 2004 Wiley利斯公司
Understanding the structural origins of differences in reduction potentials is crucial to understanding how various electron transfer proteins modulate their reduction potentials and how they evolve for diverse functional roles. Here, the high‐resolution structures of severalClostridium pasteurianumrubredoxin (Cp Rd) variants with changes in the vicinity of the redox site are reported in order to increase this understanding. Our crystal structures of [V44L] (at 1.8 Å resolution), [V44A] (1.6 Å), [V44G] (2.0 Å) and [V44A, G45P] (1.5 Å) Rd (all in their oxidized states) show that there is a gradual decrease in the distance between Fe and the amide nitrogen of residue 44 upon reduction in the size of the side chain of residue 44; the decrease occurs from leucine to valine, alanine or glycine and is accompanied by a gradual increase in their reduction potentials. Mutation of Cp Rd at position 44 also changes the hydrogen‐bond distance between the amide nitrogen of residue 44 and the sulfur of cysteine 42 in a size‐dependent manner. Our results suggest that residue 44 is an important determinant of Rd reduction potential in a manner dictated by side‐chain size. Along with the electric dipole moment of the 43‐44 peptide bond and the 44–42 NHS type hydrogen bond, a modulation mechanism for solvent accessibility through residue 41 might regulate the redox reaction of the Rds. Proteins 2004. © 2004 Wiley‐Liss, Inc.