Comparison of the γ‐crystallins isolated from eye lenses of shark and carp Unique secondary and tertiary structure of shark γ‐crystallin

FEBS Letters

Chen, S.-W.¹  Itoh, T.²  Chiou, S.-H.¹  Samejima, T.²  Kaji, H.² 

[1] Laboratory of Crystallin Research, Institute of Biochemical Sciences, National Taiwan University and Institute of Biological Chemistry, Academia Sinica, PO Box 23-106, Taipei, Taiwan ROC;Department of Chemistry, College of Science and Engineering, Aoyama Gakuin University, Setagaya-ku, Tokyo, Japan

关键词: Lens crystallin;    Chondrichthye;    Osteichthye;    Circular dichroism;    Sequence comparison;    Phylogeny;    Shark;    Carp;   

DOI  :  10.1016/0014-5793(90)81451-S

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

γ-Crystallin isolated from the shark of cartilaginous fishes was compared with the cognate γ-crystallin from the carp of bony fishes. Distinct differences in amino acid compositions, primary, secondary and tertiary structures were found. The most salient features of shark γ-crystallin lie in the fact that this crystallin possessed a significant α-helical structure in the peptide backbone as revealed by circular dichroism study, in contrast to those orthologous γ-crystallins from other vertebrate species including bony fishes which all show a predominant β-sheet secondary structure. The tertiary structure as reflected in the intrinsic microenvironments of various aromatic amino acids in the native crystallins also shows unambiguous differences between these two classes of γ-crystallins. N-Terminal sequence analysis corroborates the structural differences between shark and carp γ-crystallins. γ-Crystallin from the more primitive shark seems to be more in line with the main evolutionary phylogeny leading to the modern mammalian γ-crystallin.

【 授权许可】

Unknown