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Protein Scissors:
Site Specific Photocleavage of Proteins
Kumar, Challa1,
Buranaprapuk, Apinya1 and Thota, Jyotsna1
University of Connecticut1
Abstract-
Photocleavage of proteins, at intended sites, is of major interest for
the directed cleavage of proteins. Such methodologies can be used to
study the structures of protein-protein, protein-DNA as well as protein-ligand
complexes. A number of molecules, in this context, have been designed,
synthesized and tested in our laboratory in the past few years. Photocleavage
of proteins by a series of organic probe molecules was successful. For
example, pyrenyl peptides Py-Phe, Py-Gly-X and Py-Phe-X ((X = Trp, Tyr,
Phe, and His, and Py = 4(1-pyrenyl)butyroyl)) are prepared, and their
protein binding/photocleavage properties examined. The binding constants
with bovine serum albumin (BSA) are in the range of 107 to 105 per molar,
and binding of the probes to the proteins is evident in absorption,
fluorescence and circular dichroism spectra. Photocleavage, followed
by protein sequencing revealed the sequences where the protein cleavage
has occurred. Flash photolysis experiments indicate the formation of
pyrene cation radical as the active intermediate.
Keywords: proteinscissors,
photocleavage, pyrene, proteincleavage
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