title: Proton pathways in green fluorescence protein.
abstract: Proton pathways in green fluorescent protein (GFP) are more extended than previously reported. In the x-ray data of wild-type GFP, a two-step exit pathway exists from the active site to the protein surface, controlled by a threonine switch. A proton entry pathway begins at a glutamate-lysine cluster around Glu-5, and extends all the way to the buried Glu-222 near the active site. This structural evidence suggests that GFP may function as a portable light-driven proton-pump, with proton emitted in the excited state through the switchable exit pathway, and replenished from Glu-222 and the Glu-5 entry pathway in the ground state.
authors.affiliation: Department of Physical Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel. agmon@fh.huji.ac.il
authors.forename: Noam
authors.initials: N
authors.lastname: Agmon
mesh_terms: D000818:Animals; D001224:Aspartic Acid / Q000737:chemistry; D001665:Binding Sites; D001703:Biophysics / Q000379:methods*; D018360:Crystallography, X-Ray; D003593:Cytoplasm / Q000378:metabolism; D030562:Databases, Protein; D018698:Glutamic Acid / Q000737:chemistry; D005973:Glutamine / Q000737:chemistry; D049452:Green Fluorescent Proteins / Q000737:chemistry* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008027:Light; D008239:Lysine / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D009154:Mutation; D009584:Nitrogen / Q000737:chemistry; D017354:Point Mutation; D011487:Protein Conformation; D011522:Protons; D037401:Scyphozoa; D012997:Solvents; D013053:Spectrophotometry; D013912:Threonine / Q000737:chemistry; D013997:Time Factors; D014443:Tyrosine / Q000737:chemistry; D014867:Water / Q000737:chemistry; D014965:X-Rays
chemical_list: D011522:Protons; D012997:Solvents; D014867:Water; D005973:Glutamine; D049452:Green Fluorescent Proteins; D013912:Threonine; D001224:Aspartic Acid; D018698:Glutamic Acid; D014443:Tyrosine; D008239:Lysine; D009584:Nitrogen