Analysis of the structure and stability of omega loop A replacements in yeast iso-1-cytochrome c.
Analysis of the structure and stability of omega loop A replacements in yeast iso-1-cytochrome c.
复制标题
酵母 iso-1-细胞色素 c 中 omega 环 A 替代物的结构和稳定性分析。
DOI：
10.1002/pro.5560060122
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Burton,RE
中科院分区：
文献类型：
--
作者：
Fetrow,JS;Horner,SR;Oehrl,W;Schaak,DL;Boose,TL;Burton,RE
Omega (Ω)‐loop A, residues 18–32 in wild‐type yeast iso‐1‐cytochromec, has been deleted and replaced with loop sequences from three other cytochromescand one from esterase. Yeast expressing a partial loop deletion do not contain perceptible amounts of holoprotein as measured by low‐temperature spectroscopy and cannot grow on nonfermentable media. Strains expressing loop replacement mutations accumulate holoprotein in vivo, but the protein function varies depending on the sequence and length of the replacement loop; in vivo expression levels do not correlate with their thermal denaturation temperatures. In vitro spectroscopic studies of the loop replacement proteins indicate that all fold into a native‐like cytochromecconformation, but are less stable than the wild‐type protein. Decreases in thermal stability are caused by perturbation of loop C backbone in one case and a slight reorganization of the protein hydrophobic core in another case, rather than rearrangement of the loop A backbone. A single‐site mutation in one of the replacement mutants designed to relieve inefficient hydrophobic core packing caused by the new loop recovers some, but not all, of the lost stability.
