Effect of labeled probe conformation on analyte binding efficiency of glucose and glutamine binding proteins

BIOL 41

Ramachandram Badugu, badugu@umbc.edu1, Evangeline Amor2, Govind Rao, grao@umbc.edu1, and Leah Tolosa1. (1) Center for Advanced Sensor Technology, Department of Chemical and Biochemical Engineering, University of Maryland at Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, (2) Department of Chemistry, University of the Philippines Diliman, Quezon City, Philippines
Chemical and biochemical sensors based on fluorescence are of considerable interest. Among these, biosensors are known for their superior selectivity and specificity. For example binding proteins such as Glucose Binding Protein (GBP) and Glutamine Binding protein (QBP), obtained from periplasmic space of gram-negative bacteria, binds no other analyte except glucose and glutamine respectively. These proteins consist of two lobes connected with a hinge and exhibits analyte induced hinge motions giving rise to “closed” and “open” conformations of the protein. These protein conformational changes have been effectively monitored using solvatochromic dyes attached to the protein through a cysteine moiety obtained by site-specific mutagenesis. Subsequently, we developed glucose and glutamine fluorescence sensing devises using these proteins. For this presentation we labeled GBP and QBP with photochromic dye based on 4-styrilpyridinium bromide that shows light induced reversible cis-trans isomerism. Here in we correlate the probe structure with the protein conformation and ensuing analyte sensing efficiency.
 

Frontiers in Chemical Biology
5:00 PM-7:00 PM, Sunday, August 19, 2007 BCEC -- Exhibit Hall - B2, Poster

Division of Biological Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007