The photophysics and energy transfer dynamics of a dissymmetrical arrangement of self-assembling genetically engineered peptides that have electronically coupled intramolecular chromophores, can be studied using transient absorption spectroscopy. The polypeptides are designed at the genetic level through concatenation of KWEWX (ACAGAGAKAGAGAGAW)X (where X =1,2,3) gene casettes. These gene cassettes are then oligomerized in a second level concatenation step along a second gene cassette responsible for introducing a β-turn “TAG” codon. The DNA construct is then subject to a cloning strategy that will rapidly form repetitive polypeptide libraries. The polypeptides are designed for the placement of the K-TAG gene cassette (~(GA)3K(GA)3TAG) which codes for a lysine residue and an Amber stop codon between two KWEW segments. This strategy makes possible the comparison of D-A energy transfer kinetics among electronically coupled tryptophan donors of the asymmetrical KWEWX repeats to two separate acceptor dyes, hence, dual dye constructs. Transient absorption spectroscopy, an expedient pump-probe technique, will be used to determine which acceptor dye is first to emit fluorescence following tryptophan excitation.

Genetically engineered light gathering peptides

254th National Meeting (2017)

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