Effects of naturally occurring S47F/A mutations on the structure and function of human cytochrome c

Yan-Yan Li; Shuang-Shuang Long; Lu Yu; Ao-Kun Liu; Shu-Qin Gao; Xiangshi Tan; Ying-Wu Lin

doi:10.1016/j.jinorgbio.2023.112296

Effects of naturally occurring S47F/A mutations on the structure and function of human cytochrome c

J Inorg Biochem. 2023 Sep:246:112296. doi: 10.1016/j.jinorgbio.2023.112296. Epub 2023 Jun 17.

Authors

Yan-Yan Li¹, Shuang-Shuang Long², Lu Yu³, Ao-Kun Liu³, Shu-Qin Gao⁴, Xiangshi Tan⁵, Ying-Wu Lin⁶

Affiliations

¹ School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, China.
² School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, China. Electronic address: sslong@usc.edu.cn.
³ High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China.
⁴ Key Lab of Protein Structure and Function of Universities in Hunan Province, University of South China, Hengyang 421001, China.
⁵ Department of Chemistry & Institute of Biomedical Science, Fudan University, Shanghai 200433, China.
⁶ School of Chemistry and Chemical Engineering, University of South China, Hengyang 421001, China; Key Lab of Protein Structure and Function of Universities in Hunan Province, University of South China, Hengyang 421001, China. Electronic address: ywlin@usc.edu.cn.

PMID: 37356378
DOI: 10.1016/j.jinorgbio.2023.112296

Abstract

The sequence and structure of human cytochrome c (hCyt c) exhibit evolutionary conservations, with only a limited number of naturally occurring mutations in humans. Herein, we investigated the effects of the naturally occurring S47F/A mutations on the structure and function of hCyt c in the oxidized form. Although the naturally occurring S47F/A mutations did not largely alter the protein structure, the S47F and S47A variants exhibited a small fraction of high-spin species. Kinetic studies showed that the peroxidase activity of the variants was enhanced by ∼2.5-fold under neutral pH conditions, as well as for the rate in reaction with H₂O₂, when compared to those of wild-type hCyt c. In addition, we evaluated the interaction between hCyt c and human neuroglobin (hNgb) by isothermal titration calorimetry (ITC) studies, which revealed that the binding constant was reduced by ∼8-fold as result of the mutation of the hydrophilic Ser to the hydrophobic Phe/Ala. These findings provide valuable insights into the role of Ser47 in Ω-loop C in sustaining the structure and function of hCyt c.

Keywords: Cytochrome c; High-spin; Neuroglobin; Peroxidase activity; Protein-protein interaction.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Cytochromes c* / chemistry
Humans
Hydrogen Peroxide*
Kinetics
Mutation

Substances

Cytochromes c
Hydrogen Peroxide