Yano Jason K, Blasco Francesca, Li Huiying, Schmid Rolf D, Henne Anke, Poulos Thomas L
Department of Molecular Biology and Biochemistry, University of California, Irvine, California 92697-3900, USA.
J Biol Chem. 2003 Jan 3;278(1):608-16. doi: 10.1074/jbc.M206568200. Epub 2002 Oct 24.
The second structure of a thermophile cytochrome P450, CYP175A1 from the thermophilic bacterium Thermus thermophilus HB27, has been solved to 1.8-A resolution. The overall P450 structure remains conserved despite the low sequence identity between the various P450s. The CYP175A1 structure lacks the large aromatic network found in the only other thermostable P450, CYP119, thought to contribute to thermal stability. The primary difference between CYP175A1 and its mesophile counterparts is the investment of charged residues into salt-link networks at the expense of single charge-charge interactions. Additional factors involved in the thermal stability increase are a decrease in the overall size, especially shortening of loops and connecting regions, and a decrease in the number of labile residues such as Asn, Gln, and Cys.
嗜热菌嗜热栖热菌HB27的细胞色素P450的第二个结构，即CYP175A1，已解析到1.8埃的分辨率。尽管各种P450之间的序列同一性较低，但整体P450结构仍保持保守。CYP175A1结构缺乏在另一种唯一的耐热P450即CYP119中发现的有助于热稳定性的大芳香网络。CYP175A1与其嗜温对应物之间的主要差异在于带电残基投入盐键网络，代价是单个电荷 - 电荷相互作用。热稳定性增加所涉及的其他因素包括整体尺寸减小，特别是环和连接区域缩短，以及不稳定残基（如天冬酰胺、谷氨酰胺和半胱氨酸）数量减少。
