Recombinant avidin and avidin-fusion proteins

Both chicken egg-white avidin and its bacterial relative streptavidin are w ell known for their extraordinary high affinity with biotin (K-d similar to 10(-15) M). They are widely used as tools in a number of affinity-based se parations, in diagnostic assays and in a variety of other applications. The se methods have collectively become known as (strept)avidin-biotin technolo gy. Biotin can easily and effectively be attached to different molecules, t ermed binders and probes, without destroying their biological activity. The exceptional stability of the avidin-biotin complex and the wide range of c ommercially available reagents explain the popularity of this system. In or der by genetic engineering to modify the unwanted properties of avidin and to further expand the existing avidin-biotin technology, production systems for recombinant avidin and avidin-fusion proteins have been established. T his review article presents an overview of the current status of these syst ems. Future trends in the production and applications of recombinant avidin and avidin-fusion proteins are also discussed. (C) 1999 Elsevier Science B .V. All rights reserved.