A structural model for the α‐subunit of transducin Implications of its role as a molecular switch in the visual signal transduction mechanism

FEBS Letters

Hingorani, Vijay N.¹  Ho, Yee-Kin¹ 

[1] Department of Biological Chemistry, University of Illinois at Chicago, Health Sciences Center, Chicago, IL. 60612, USA

关键词: Transducin;    GTP-binding protein;    Protein folding;    Visual signal transduction;    Retinal cyclic GMP cascade;    Enzyme mechanism;   

DOI  :  10.1016/0014-5793(87)80867-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Transducin is a GTP-binding protein which mediates the light activation signal from photolyzed rhodopsin to cGMP phosphodiesterase and is pivotal in the visual excitation process. Biochemical studies suggest that the T_α subunit of transducin is composed of three functional domains, one for rhodopsin/T_βγ interaction, another for guanine nucleotide binding, and a third for the activation of phosphodiesterase. The integration of the primary sequence of T_α along with secondary structure, hydropathy and folding topology predictions, and a comparison with homologous proteins have led to the construction of a three-dimensional model of the T_α subunit. A molecular mechanism which underlies the coupling action of T_α is suggested on the basis of this model.

【 授权许可】

Unknown