title: Electronic structure of the PYP chromophore in its native protein environment.
abstract: We report on supermolecular ab initio calculations which clarify the role of the local amino acid environment in determining the unique electronic structure properties of the photoactive yellow protein (PYP) chromophore. The extensive ab initio calculations, at the level of the CC2 and EOM-CCSD methods, allow us to explicitly address how the interactions between the deprotonated p-coumaric thio-methyl ester (pCTM-) chromophore and the surrounding amino acids act together to create a specifically stabilized pCTM- species. Particularly noteworthy is the role of the Arg52 amino acid in stabilizing the chromophore against autoionization, and the role of the Tyr42 and Glu46 amino acids in determining the hydrogen-bonding properties that carry the dominant energetic effects.
authors.affiliation: Theoretische Chemie, Physikalisch-Chemisches Institut Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany. evgeniy.gromov@pci.uni-heidelberg.de
authors.forename: Evgeniy V
authors.initials: EV
authors.lastname: Gromov
authors.forename: Irene
authors.initials: I
authors.lastname: Burghardt
authors.forename: Horst
authors.initials: H
authors.lastname: Köppel
authors.forename: Lorenz S
authors.initials: LS
authors.lastname: Cederbaum
mesh_terms: D000595:Amino Acid Sequence; D001120:Arginine / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry*; D003545:Cysteine / Q000737:chemistry; D018698:Glutamic Acid / Q000737:chemistry; D008958:Models, Molecular; D010649:Phenylalanine / Q000737:chemistry; D020283:Photoreceptors, Microbial / Q000737:chemistry*; D013912:Threonine / Q000737:chemistry; D014443:Tyrosine / Q000737:chemistry; D014633:Valine / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D020283:Photoreceptors, Microbial; C050162:photoactive yellow protein, Bacteria; D013912:Threonine; D018698:Glutamic Acid; D014443:Tyrosine; D010649:Phenylalanine; D001120:Arginine; D014633:Valine; D003545:Cysteine