Download MendeleyStructural and functional insights into thermally stable cytochrome c' from a thermophile
Fujii, S., Oki, H., Kawahara, K., Yamane, D., Yamanaka, M., Maruno, T., Kobayashi, Y., Masanari, M., Wakai, S., Nishihara, H., Ohkubo, T., Sambongi, Y.(2017) Protein Sci 26: 737-748
- PubMed: 28097774
- DOI: https://doi.org/10.1002/pro.3120
- Primary Citation of Related Structures:
5B3I - PubMed Abstract:
Thermophilic Hydrogenophilus thermoluteolus cytochrome c' (PHCP) exhibits higher thermal stability than a mesophilic counterpart, Allochromatium vinosum cytochrome c' (AVCP), which has a homo-dimeric structure and ligand-binding ability. To understand the thermal stability mechanism and ligand-binding ability of the thermally stable PHCP protein, the crystal structure of PHCP was first determined. It formed a homo-dimeric structure, the main chain root mean square deviation (rmsd) value between PHCP and AVCP being 0.65 Å. In the PHCP structure, six specific residues appeared to strengthen the heme-related and subunit-subunit interactions, which were not conserved in the AVCP structure. PHCP variants having altered subunit-subunit interactions were more severely destabilized than ones having altered heme-related interactions. The PHCP structure further revealed a ligand-binding channel and a penta-coordinated heme, as observed in the AVCP protein. A spectroscopic study clearly showed that some ligands were bound to the PHCP protein. It is concluded that the dimeric PHCP from the thermophile is effectively stabilized through heme-related and subunit-subunit interactions with conservation of the ligand-binding ability. We report the X-ray crystal structure of cytochrome c' (PHCP) from thermophilic Hydrogenophilus thermoluteolus. The high thermal stability of PHCP was attributed to heme-related and subunit-subunit interactions, which were confirmed by a mutagenesis study. The ligand-binding ability of PHCP was examined by spectrophotometry. PHCP acquired the thermal stability with conservation of the ligand-binding ability. This study furthers the understanding of the stability and function of cytochromes c.
Organizational Affiliation:
Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan.
