Dr. Melik Demirel, Assistant Professor of Engineering Science and Mechanics and immediate past Pearce Development Professor will present a talk entitled "How do insertions affect Green Fluorescent Protein?" on Wednesday, February 7, 2007, as part of Arizona State University's Biological Physics Seminar for spring 2007. An abstract of the talk follows.

The green fluorescent protein (GFP) is an intrinsically fluorescent protein extracted from the jellyfish Aequorea victoria. The GFP chromophore formation and its mutants have been extensively studied. However, a precise understanding of fluorescence loss is still lacking. Particularly, our aim is to create GFP molecules carrying random amino acids insertions and understand the effect of these insertions (e.g.by change in excitation and emission) experimentally and computationally. A computer-based modeling and bench-top experiments are combined to understand the fluorescence of GFP. Random octapeptides are inserted into individual loops of the GFP. Amino acid sequences and fluorescence levels of clones from each loop are determined. The effect of peptide insertions into the loop regions of GFP are studied computationally using quantum mechanics and molecular dynamics calculations. Both computational and experimental results show that random peptide insertions change the excitation and emission intensity of GFP. We showed that the location of the peptide insertion affects the fluorescence levels of the GFP.