Investigation of the solution conformation of cytochrome c-551 from Pseudomonas stutzeri.
Investigation of the solution conformation of cytochrome c-551 from Pseudomonas stutzeri.
复制标题
研究施氏假单胞菌细胞色素 c-551 的溶液构象。
DOI：
10.1021/bi00151a030
复制
发表时间：
1992
期刊：
影响因子：
2.9
通讯作者：
Timkovich,R
中科院分区：
文献类型：
--
作者：
Cai,M;Bradford,EG;Timkovich,R
摘要：核磁共振光谱和溶液结构计算已被用于检查从施氏假单胞菌（ATCC 17588）的铁细胞色素c-551。共振分配提出了所有的主链和大多数侧链质子。距离限制是根据质子对之间的核奥弗豪泽增强来确定的。二面角的限制，确定从估计的定标器耦合常数。根据1033个质子间距离和57个扭转角约束条件，采用距离几何方法计算了24种结构，并通过能量最小化和模拟退火方法进行了优化。主链和侧链的原子都是明确的，除了残基34-40周围的环区域，前两个残基在N-末端，最后两个在C-末端，和一些侧链位于分子表面上。24个独立结构和通过平均其坐标获得的平均结构之间的等效原子位置的平均均方根偏差对于主链原子为0.54 <$0.08 <$10，对于残基3-80的所有非氢原子加上血红素基团为0.97 <$0.09 <$10。将这些结构与来自铜绿假单胞菌的类似蛋白质细胞色素c-551的X射线晶体学结构进行比较[Matsuura，Takano，& Dickerson（1982）J. Mol. Biol. 156，389 -409）。主链的折叠模式非常一致，但也有一些差异。细胞色素c-551是原核生物中发现的电子传递蛋白，其功能与真核生物中的细胞色素c相同。用约它们是表达C型细胞色素的所有关键特征的简化版本。结构和功能的比较已被综述（Kamen & Horio，1970; Dickerson & Timkovich，1975; Meyer & Kamen，1982）。细胞色素c-551包含具有序列同源性的家族。几个氨基酸序列是已知的（Ambler，1982），并且容易比对，显示出严格保守的区域，可以解释为中性取代的变化区域（即，大小和近似疏水性的保守），和
Revised Manuscript Received June 24, 1992 abstract: NMR spectroscopy and solution structure computations have been used to examine ferrocytochrome c-551 from Pseudomonas stutzeri (ATCC 17588). Resonance assignments are proposed for all main-chain and most side-chain protons. Distance constraints were determined on the basis of nuclear Overhauser enhancements between pairs of protons. Dihedral angle constraints were determined from estimates of scaler coupling constants. Twenty-four structures were calculated by distance geometry and refined by energy minimization and simulated annealing on the basis of 1033 interproton distanceand 57 torsion angle constraints. Both the main-chain and side-chain atoms are well definedexcept for a loop region around residues 34-40, the first two residues at the N-terminus and the last two at the C-terminus, and some side chains located on the molecular surface. The average root mean squared deviation in position for equivalent atoms between the 24 individual structures and the mean structure obtained by averaging their coordinates is 0.54 ą 0.08 Á for the main-chain atoms and 0.97 ą 0.09 Á for all non-hydrogen atoms of residues 3-80 plus the heme group. These structures were compared to the X-ray crystallographic structure of an analogous protein, cytochrome c-551 from Pseudomonas aeruginosa [Matsuura, Takano, & Dickerson (1982) J. Mol. Biol. 156,389-409). The main-chain folding patterns are very consistent, but there are some differences. The largest difference is in a surface loop segment from residues 34 to 40.Cytochromes c-551 are electron transport proteins found in prokaryotes, where they perform the same function as cytochrome c in eukaryotes. With ca. 82 amino acids they are simplified versions that express all the key characteristics of c-type cytochromes. Comparisons of structure and function have been reviewed (Kamen & Horio, 1970; Dickerson & Timkovich, 1975; Meyer & Kamen, 1982). Cytochromes c-551 comprise a family with sequence homologies. Several amino acid sequences are known (Ambler, 1982) and are readily aligned, showing regions of strict conservation, regions of change that can be interpreted as neutral substitutions (ie, conservation of size and approximate hydrophobicity), and