MODIFIED AVIDIN AND STREPTAVIDIN MOLECULES AND USE THEREOF

摘要

PCT No. PCT/IL96/00014 Sec. 371 Date Mar. 5, 1998 Sec. 102(e) Date Mar. 5, 1998 PCT Filed Jun. 13, 1996 PCT Pub. No. WO97/00329 PCT Pub. Date Jan. 3, 1997Biotin-binding modified avidin-type molecules are provided in which the essential tyrosine residue in the biotin-binding site is modified in such a way that its pKa is decreased in comparison to the pKa of the unmodified tyrosine residue in the corresponding unmodified avidin-type molecule. The avidin-type molecules include: (i) native egg-white avidin; (ii) recombinant avidin; (iii) deglycosylated forms of avidin; (iv) bacterial streptavidin; (v) recombinant streptavidin; (vi) truncated streptavidin; and (vii) derivatives of (i)-(vi) which are modified at sites other than the essential tyrosine residue. The modification is achieved by substitution at one or both ortho positions to the hydroxy radical of the tyrosine residue by radicals such as nitro, halogen, azo and amino. The modified avidin-type molecules can be used in all applications of the avidin-biotin technology.