Solid-State NMR Spectroscopic Study of Chromophore-Protein Interactions in the Pr Ground State of Plant Phytochrome A  

作　　者：Chen Song Lars-Oliver Essen Wolfgang Ga＇rtner Jon Hughes J6rg Matysik 

机构地区：[1]Leids Instituut voor Chemisch Onderzoek, Universiteit Leiden, PO Box 9502, 2300 RA Leiden, The Netherlands [2]Fachbereich Chemie, Philipps-Universita＇t Marburg, Hans-Meerwein-Stral3e, D-35032 Marburg, Germany [3]Max-Planck-lnstitut for Bioanorganische Chemie, StiftstraBe 34-36, D-45470 MCu＇lheim an der Ruhr, Germany [4]Pflanzenphysiologie, Justus-Liebig-Universita＇t, SenckenbergstraBe 3, D-35390 Giessen, Germany

出　　处：《Molecular Plant》2012年第3期698-715,共18页分子植物（英文版）

摘　　要：Despite extensive study, the molecular structure of the chromophore-binding pocket of phytochrome A （phyA）, the principal photoreceptor controlling photomorphogenesis in plants, has not yet been successfully resolved. Here, we report a series of two-dimensional （2-D） magic-angle spinning solid-state NMR experiments on the recombi- nant N-terminal, 65-kDa PAS-GAF-PHY light-sensing module of phytochrome A3 from oat （Avena sativa）, assembled with uniformly 13C- and lSN-labeled phycocyanobilin （u-[13C,15N]-PCB-As.phyA3）. The Pr state of this protein was studied regarding the electronic structure of the chromophore and its interactions with the proximal amino acids. Using 2-D 13C-13C and 1HJSN experiments, a complete set of 13C and 15N assignments for the chromophore were obtained. Also, a large number of 1H-13C distance restraints between the chromophore and its binding pocket were revealed by inter- facial heteronuclear correlation spectroscopy. 13C doublings of the chromophore A-ring region and the C-ring carbox- ylate moiety, together with the observation of two Pr isoforms, Pr-I and Pr-II, demonstrate the local mobility of the chromophore and the plasticity of its protein environment. It appears that the interactions and dynamics in the binding pocket of phyA in the Pr state are remarkably similar to those of cyanobacterial phytochrome （Cphl）. The N-terminus of the region modeled （residues 56-66 of phyA） is highly mobile. Differences in the regulatory processes involved in plant and Cphl phytochromes are discussed.Despite extensive study, the molecular structure of the chromophore-binding pocket of phytochrome A （phyA）, the principal photoreceptor controlling photomorphogenesis in plants, has not yet been successfully resolved. Here, we report a series of two-dimensional （2-D） magic-angle spinning solid-state NMR experiments on the recombi- nant N-terminal, 65-kDa PAS-GAF-PHY light-sensing module of phytochrome A3 from oat （Avena sativa）, assembled with uniformly 13C- and lSN-labeled phycocyanobilin （u-[13C,15N]-PCB-As.phyA3）. The Pr state of this protein was studied regarding the electronic structure of the chromophore and its interactions with the proximal amino acids. Using 2-D 13C-13C and 1HJSN experiments, a complete set of 13C and 15N assignments for the chromophore were obtained. Also, a large number of 1H-13C distance restraints between the chromophore and its binding pocket were revealed by inter- facial heteronuclear correlation spectroscopy. 13C doublings of the chromophore A-ring region and the C-ring carbox- ylate moiety, together with the observation of two Pr isoforms, Pr-I and Pr-II, demonstrate the local mobility of the chromophore and the plasticity of its protein environment. It appears that the interactions and dynamics in the binding pocket of phyA in the Pr state are remarkably similar to those of cyanobacterial phytochrome （Cphl）. The N-terminus of the region modeled （residues 56-66 of phyA） is highly mobile. Differences in the regulatory processes involved in plant and Cphl phytochromes are discussed.

关 键 词：solid-state NMR plant phytochrome chromophore-protein interaction signal transduction 

分 类 号：O657.2[理学—分析化学] Q946.1[理学—化学]