title: Dissecting the key residues crucial for the species-specific thermostability of muscle-type creatine kinase.
abstract: Species-specific protein thermal stability is closely correlated to the living conditions of the organism, especially to its body temperature. In this research, human and zebrafish muscle-type creatine kinases (MMCKs) were taken as model proteins to investigate the molecular adaptation of proteins in poikilothermal and homoiothermal animals. Both the optimal temperature for catalysis and the thermal stability of human MMCK was much higher than those of zebrafish MMCK. Sequence alignment identified 9 amino acid variations conserved in either the teleost MMCKs or the mammal and electric ray MMCKs. Bidirectional mutations were performed to find the residues with beneficial mutations. The results showed that two residues close to the dimer interface of MMCK, the 46th and 146th residue, were crucial for species-specific thermal stability.
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing, China.
authors.forename: Yan-Song
authors.initials: YS
authors.lastname: Gao
authors.forename: Yin
authors.initials: Y
authors.lastname: Wang
authors.forename: Chang
authors.initials: C
authors.lastname: Li
authors.forename: Zhe
authors.initials: Z
authors.lastname: Chen
authors.forename: Yong-Bin
authors.initials: YB
authors.lastname: Yan
authors.forename: Hai-Meng
authors.initials: HM
authors.lastname: Zhou
mesh_terms: D000222:Adaptation, Physiological; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D017124:Conserved Sequence; D052283:Creatine Kinase, MM Form / Q000737:chemistry* / Q000378:metabolism; D004285:Dogs; D004795:Enzyme Stability; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011817:Rabbits; D016415:Sequence Alignment; D013045:Species Specificity; D013696:Temperature; D013816:Thermodynamics; D015027:Zebrafish
chemical_list: D052283:Creatine Kinase, MM Form