title: Complete Proton Transfer Cycle in GFP and Its T203V and S205V Mutants.
abstract: Proton transfer is critical in many important biochemical reactions. The unique three-step excited-state proton transfer in avGFP allows observations of protein proton transport in real-time. In this work we exploit femtosecond to microsecond transient IR spectroscopy to record, in D2 O, the complete proton transfer photocycle of avGFP, and two mutants (T203V and S205V) which modify the structure of the proton wire. Striking differences and similarities are observed among the three mutants yielding novel information on proton transfer mechanism, rates, isotope effects, H-bond strength and proton wire stability. These data provide a detailed picture of the dynamics of long-range proton transfer in a protein against which calculations may be compared.
authors.affiliation: School of Chemistry, University of East Anglia, Norwich, NR4 7TJ (UK).
authors.forename: Sergey P
authors.initials: SP
authors.lastname: Laptenok
authors.affiliation: School of Chemistry, University of East Anglia, Norwich, NR4 7TJ (UK).|Department of Biophysics, Medical School, Szigeti str. 12, 7624 Pécs (Hungary).
authors.forename: Andras
authors.initials: A
authors.lastname: Lukacs
authors.affiliation: Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400 (USA).
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Gil
authors.affiliation: Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400 (USA).|The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458 (USA).
authors.forename: Richard
authors.initials: R
authors.lastname: Brust
authors.affiliation: Central Laser Facility, Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0QX (UK).
authors.forename: Igor V
authors.initials: IV
authors.lastname: Sazanovich
authors.affiliation: Central Laser Facility, Research Complex at Harwell, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0QX (UK).
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Greetham
authors.affiliation: Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400 (USA). peter.tonge@stonybrook.edu.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Tonge
authors.affiliation: School of Chemistry, University of East Anglia, Norwich, NR4 7TJ (UK). s.meech@uea.ac.uk.
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Meech
mesh_terms: D000818:Animals; D049452:Green Fluorescent Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006860:Hydrogen Bonding; D037402:Hydrozoa / Q000378:metabolism; D007700:Kinetics; D016297:Mutagenesis, Site-Directed; D017434:Protein Structure, Tertiary; D011522:Protons; D013055:Spectrophotometry, Infrared
chemical_list: D011522:Protons; D049452:Green Fluorescent Proteins
keywords: IR spectroscopy; green fluorescent protein (GFP); kinetic isotope effect; proton transfer; ultrafast spectroscopy