title: Functional characterization and expression analysis of myoglobin in high-altitude lizard Phrynocephalus erythrurus.
abstract: Myoglobin (Mb) is a monomeric hemoprotein which plays an important role in oxygen storage and transport in cardiac and skeletal muscle under hypoxia. The red tail toad-headed lizard Phrynocephalus erythrurus (Lacertilia: Agamidae), which inhabits at an elevation of 4500-5300 m on the Qinghai-Tibetan plateau, is known to be the highest living lizard in the world. To investigate the characters of myoglobin of this unique species, another low altitude lizard Phrynocephalus przewalskii (Lacertilia: Agamidae) was selected as a reference. The open reading frame (ORF) of myoglobin in two lizards was 465 bp which encodes a polypeptide of 154 amino acids with different theoretical molecular weight and isoelectric point. The amino acid substitutions of myoglobin between two species were found at Thr13Ile, Lys87Thr and His118Asn. Homology modeling results indicated that P. erythrurus myoglobin has a greater heme pocket, which may be more favorable to oxygen binding and unloading. On the other hand, the mRNA levels of myoglobin in both cardiac and skeletal muscle in P. erythrurus were significantly larger than those in low altitude P. przewalskii. At protein level, myoglobin concentration in skeletal muscle in P. erythrurus was notably increased, but no significant difference was observed in cardiac muscle.
authors.affiliation: Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Xin
authors.affiliation: Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, China.
authors.forename: Xiaolong
authors.initials: X
authors.lastname: Tang
authors.affiliation: Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, China.
authors.forename: Huihui
authors.initials: H
authors.lastname: Wang
authors.affiliation: Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, China.
authors.forename: Songsong
authors.initials: S
authors.lastname: Lu
authors.affiliation: Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Institute of Biochemistry and Molecular Biology, School of Life Science, Lanzhou University, Lanzhou, China. Electronic address: chenq@lzu.edu.cn.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Chen
mesh_terms: D000064:Acclimatization; D000531:Altitude; D000818:Animals; D008116:Lizards / Q000235:genetics / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D009211:Myoglobin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D030162:Reptilian Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D009211:Myoglobin; D012333:RNA, Messenger; D030162:Reptilian Proteins
keywords: Acclimatization; Adaptation; Hypoxia; Myoglobin; Phrynocephalus erythrurus