title: Trapping the P+B(L)- initial intermediate state of charge separation in photosynthetic reaction centers from Rhodobacter capsulatus.
abstract: The short-lived (<1 ps) initial intermediate state P(+)B(L)(-) in the photoinduced charge separation process of the bacterial photosynthetic reaction center has been trapped in two D(LL)-based Rhodobacter capsulatus mutants that have Tyr at position M208 and lack the bacteriopheophytin electron acceptor H(L). Transient state P(+)B(L)(-) is characterized by a 1017 nm bacteriochlorophyll anion absorption band and decays by charge recombination with a lifetime of several hundred picoseconds at 295 K. P(+)B(L)(-) is not observed in an otherwise identical mutant that has Phe at M208, which appears to make the state thermodynamically inaccessible from the excited primary electron donor P*.
authors.affiliation: Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA.
authors.forename: Brett
authors.initials: B
authors.lastname: Carter
authors.forename: Steven G
authors.initials: SG
authors.lastname: Boxer
authors.forename: Dewey
authors.initials: D
authors.lastname: Holten
authors.forename: Christine
authors.initials: C
authors.lastname: Kirmaier
mesh_terms: D007700:Kinetics; D008958:Models, Molecular; D010674:Pheophytins / Q000737:chemistry* / Q000378:metabolism; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D016354:Rhodobacter capsulatus / Q000378:metabolism*
chemical_list: D010674:Pheophytins; D045322:Photosynthetic Reaction Center Complex Proteins; C006678:bacteriopheophytin