Kato Yuki, Fujii Sotaro, Kuribayashi Taka-aki, Masanari Misa, Sambongi Yoshihiro
a Graduate School of Biosphere Science , Hiroshima University , Higashi-Hiroshima , Japan.
Biosci Biotechnol Biochem. 2015;79(7):1125-9. doi: 10.1080/09168451.2015.1015956. Epub 2015 Mar 10.
Cytochrome c' (SACP) from mesophilic Shewanella amazonensis, growing optimally at 37 °C, was thermally more stable than cytochrome c' (AVCP) from mesophilic Allochromatium vinosum, growing optimally at 25 °C. In contrast, SACP was less stable than cytochrome c' (PHCP) from thermophilic Hydrogenophilus thermoluteolus, growing optimally at 52 °C. Although only 28% of the SACP amino acid sequence was identical to those of AVCP and PHCP, the latter two being 55% identical, the overall main chain structures of the three cytochromes c' were similar, and SACP exhibited thermal stability intermediate between those of AVCP and PHCP. For these three proteins, the higher the stability is, the lesser the number of Gly residues in the putative α-helical regions is. Cytochromes c' including the present three are suitable for examining the protein stabilization mechanisms, because they are structurally similar and available from environments with a wide range of temperatures.
来自嗜温亚马逊希瓦氏菌（在37°C时生长最佳）的细胞色素c'（SACP）在热稳定性上比来自嗜温嗜硫红假单胞菌（在25°C时生长最佳）的细胞色素c'（AVCP）更高。相比之下，SACP比来自嗜热嗜热栖热菌（在52°C时生长最佳）的细胞色素c'（PHCP）稳定性更低。尽管SACP的氨基酸序列只有28%与AVCP和PHCP相同，而后两者的序列相似度为55%，但这三种细胞色素c'的整体主链结构相似，且SACP的热稳定性介于AVCP和PHCP之间。对于这三种蛋白质，稳定性越高，假定α螺旋区域中的甘氨酸残基数量越少。包括目前这三种在内的细胞色素c'适合用于研究蛋白质稳定机制，因为它们结构相似且可从具有广泛温度范围的环境中获得。
