Yamane-Koshizawa Daisuke, Fujii Sotaro, Maruno Takahiro, Kobayashi Yuji, Yamanaka Masaru, Wakai Satoshi, Sambongi Yoshihiro
a Graduate School of Biosphere Science , Hiroshima University , Higashi-Hiroshima , Japan.
b Global Career Design Center , Hiroshima University , Higashi-Hiroshima , Japan.
Biosci Biotechnol Biochem. 2018 Feb;82(2):304-311. doi: 10.1080/09168451.2017.1419856. Epub 2018 Jan 12.
AVCP cytochrome c' from mesophilic Allochromatium vinosum exhibits lower stability than a thermophilic counterpart, Hydrogenophilus thermoluteolus cytochrome c' (PHCP), in which the six specific amino acid residues that are not conserved in AVCP are responsible for its stability. Here we measured the stability of AVCP variants carrying these specific residues instead of the original AVCP ones. Among the six single AVCP variants, all of which formed a dimeric structure similar to that of the wild-type, three were successfully stabilized compared with the wild-type, while one showed lower stability than the wild-type. In addition, the most stabilized and destabilized AVCP variants could bind CO, similar to the wild-type. These results indicated that mesophilic AVCP could be stabilized through specific three mutations modeled by the thermophilic counterpart, PHCP, without changing the CO binding ability.
嗜温性嗜酒色杆菌的AVCP细胞色素c'比嗜热性嗜热栖热放线菌的细胞色素c'（PHCP）稳定性更低，在AVCP中不保守的六个特定氨基酸残基决定了其稳定性。在此，我们测定了携带这些特定残基而非原始AVCP残基的AVCP变体的稳定性。在六个单一AVCP变体中，所有变体均形成了与野生型相似的二聚体结构，其中三个与野生型相比成功实现了稳定，而一个变体的稳定性低于野生型。此外，与野生型相似，最稳定和最不稳定的AVCP变体都能结合CO。这些结果表明，嗜温性AVCP可以通过以嗜热性对应物PHCP为模型的特定三个突变实现稳定，而不改变CO结合能力。
