Dolla A, Florens L, Bruschi M, Dudich I V, Makarov A A
Unite de Bioénergétique et Ingéniérie des Proteines-CNRS, Marseille, France.
Biochem Biophys Res Commun. 1995 Jun 26;211(3):742-7. doi: 10.1006/bbrc.1995.1875.
The thermostability of wild type Desulfovibrio vulgaris Hildenborough tetraheme cytochrome c3 and its H22M, H25M, H35M and H70M mutants was studied by circular dichroism technique in the far UV and Soret regions. It was shown that wild type cytochrome is extremely thermostable and retains structural and functional properties up to 110 degrees C. Mutations do not change overall secondary structure and local structure of the hemes vicinity. All mutants are much more unstable to heat denaturation than the wild type cytochrome. Point mutation (His/Met replacement) results in extraordinary 30-45 degrees C decrease in the protein thermostability depending on the mutation. We may conclude therefore that the heme region is important not only for the functional properties of the cytochrome but also for the overall protein thermostability.
利用圆二色光谱技术，在远紫外区和索雷特区研究了野生型希登伯勒嗜热脱硫弧菌四血红素细胞色素c3及其H22M、H25M、H35M和H70M突变体的热稳定性。结果表明，野生型细胞色素具有极高的热稳定性，在高达110℃时仍保留其结构和功能特性。突变并未改变整体二级结构以及血红素附近的局部结构。所有突变体相较于野生型细胞色素，对热变性的稳定性要低得多。点突变（组氨酸/甲硫氨酸替换）导致蛋白质热稳定性异常降低30 - 45℃，具体降低幅度取决于突变情况。因此，我们可以得出结论，血红素区域不仅对细胞色素的功能特性很重要，而且对蛋白质的整体热稳定性也很重要。
