Mapping of loops in red fluorescent protein for application in single-step assays

ANYL 168

Yasmeen Rahimi1, Suresh Shrestha2, Tanushree Banerjee1, and Sapna K Deo2. (1) Department of Chemistry & Chemical Biology, Indiana University Purdue University Indianapolis, 402 N. Blackford Street, LD326, Indianapolis, IN 46202, (2) Department of Chemistry and Chemical Biology, Indiana University Purdue University Indianapolis, 402 N Blackford St, LD 326, Indianapollis, IN 46202
Availability of genes of a variety of reporters provides versatility for bioanalysis since they can be manipulated genetically and can be employed in the detection of analytes of interest in conjunction with antibodies or binding proteins for the respective analytes. A red fluorescent protein (DsRed) has become a popular fusion tag. We have demonstrated for the first time application of DsRed monomer as a quantitative label in single-step assays. To achieve that, we examined the X-ray crystal structure of DsRed monomer targeting loop regions of the protein. The introduction of a unique cysteine at different solvent-exposed loops of the protein allowed us to attach a maleimide derivative of biotin to the protein through sulfhydryl of the unique cysteine. The sites selected were such that the biotin attached through unique cysteine is structurally close to the fluorophore and any binding events occurring at this site will be transduced to the DsRed fluorophore. A change in the fluorescence of DsRed upon addition of avidin, which binds to biotin was evaluated.

 

General Papers
7:00 PM-9:00 PM, Sunday, 10 September 2006 Moscone Center -- Hall D, Poster

Division of Analytical Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006