The structure of the complex between avidin and the dye, 2‐(4'‐hydroxyazobenzene) benzoic acid (HABA)

FEBS Letters

Sussman, Joel L.²  Bayer, Edward A.¹  Livnah, Oded²  Wilchek, Meir¹ 

[1] Department of Biophysics, The Weizmann Institute of Science, Rehovot 76100, Israel;Department of Structural Biology, The Weizmann Institute of Science, Rehovot 76100, Israel

关键词: Avidin;    Streptavidin;    Biotin-binding site;    HABA;    Biomimetics;    Protein structure;    X-ray crystallography;   

DOI  :  10.1016/0014-5793(93)80986-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The crystal structure of the complex formed between the egg-white biotin-binding protein, avidin, and the dye, 2-(4'-hydroxyazobenzene) benzoic acid (HABA), was determined to a resolution of 2.5 A. The interaction of avidin with the benzoate ring of HABA is essentially identical to that of the complex formed between HABA and streptavidin (the bacterial analogue of the egg-white protein). This interaction emulates the definitive high-affinity interaction of both proteins with the ureido moiety of biotin. The major difference between the avidin- and streptavidin-HABA complexes lies in their interaction with the hydroxyphenyl ring of the dye molecule; in avidin, two adjacent amino acid residues (Phe⁷² and Ser⁷³), which are not present in streptavidin, form additional interactions with this ring. These are suggested to account for the higher affinity of avidin for HABA. The characteristic red shift, which accompanies the interaction of both proteins with the dye, was traced to a proposed charge-transfer complex formed between the hydroxyphenyl ring of HABA and the indole ring of Trp⁷⁰ in avidin (Trp⁷⁹ in streptavidin). Comparison of binding site residues of two such similar proteins versus their markedly different affinities for two such different substrates should eventually contribute to a better design of biomimetic reagents and drugs.

【 授权许可】

Unknown