title: Locked 5Zs-biliverdin blocks the Meta-RA to Meta-RC transition in the functional cycle of bacteriophytochrome Agp1.
abstract: The bacteriophytochrome Agp1 was reconstituted with a locked 5Zs-biliverdin in which the C(4)=C(5) and C(5)-C(6) bonds of the methine bridge between rings A and B are fixed in the Z and syn configuration/conformation, respectively. In Agp1-5Zs the photoconversion proceeds via the Lumi-R intermediate to Meta-R(A), but the following millisecond-transition to Meta-R(C) is blocked. Consistently, no transient proton release was detected. The photoconversion of Agp1-5Zs is apparently arrested in a Meta-R(A)-like intermediate, since the subsequent syn to anti rotation around the C(5)-C(6) bond is prevented by the lock. The Meta-R(A)-like photoproduct was characterized by its distinctive CD spectrum suggesting a reorientation of ring D.
authors.affiliation: Department of Physics, Freie Universität Berlin, D-14195 Berlin, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Seibeck
authors.forename: Berthold
authors.initials: B
authors.lastname: Borucki
authors.forename: Harald
authors.initials: H
authors.lastname: Otto
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Inomata
authors.forename: Htoi
authors.initials: H
authors.lastname: Khawn
authors.forename: Hideki
authors.initials: H
authors.lastname: Kinoshita
authors.forename: Norbert
authors.initials: N
authors.lastname: Michael
authors.forename: Tilman
authors.initials: T
authors.lastname: Lamparter
authors.forename: Maarten P
authors.initials: MP
authors.lastname: Heyn
mesh_terms: D026921:Amino Acid Transport Systems, Neutral / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D001664:Biliverdine / Q000737:chemistry / Q000494:pharmacology*; D002942:Circular Dichroism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008027:Light; D015394:Molecular Structure; D010777:Photochemistry; D010834:Phytochrome / Q000737:chemistry / Q000378:metabolism*; D011522:Protons
chemical_list: D026921:Amino Acid Transport Systems, Neutral; D001426:Bacterial Proteins; D011522:Protons; D010834:Phytochrome; D001664:Biliverdine