title: New Insight into the Water-Soluble Chlorophyll-Binding Protein from Lepidium virginicum.
abstract: This study describes new recombinant water-soluble chlorophyll (Chl)-binding proteins (WSCP) from Lepidium virginicum (LvWSCP). This complex binds four Chls (i.e. two dimers of Chls) per protein tetramer. We show that absorption, emission, hole-burned (HB) spectra and the shape of the zero-phonon hole (ZPH) action spectrum are consistent with the presence of uncorrelated excitation energy transfer between two Chl dimers. Thus, there is no need to include slow protein relaxation within the lowest excited state (as suggested in a previous analysis of cauliflower WSCP [Schmitt, F.-J. et al. (2008) J. Phys. Chem. B, 112, 13951; Pieper, J. et al. (2011) J. Phys. Chem. B, 115, 4053]) in order to explain the large shift observed between the maxima of the ZPH action and emission spectra. Experimental evidence is provided which shows that electron exchange between lowest energy Chls and the protein may occur, i.e. electrons can be trapped at low temperature by nearby aromatic amino acids. The latter explains the shape of nonresonant HB spectra (i.e. the absence of antihole), demonstrating that the hole-burning process in LvWSCP is largely photochemical in nature, though a small contribution from nonphotochemical hole burning (in resonant holes) is also observed.
authors.affiliation: Department of Chemistry, Kansas State University, Manhattan, Kansas, 66506.
authors.forename: Adam
authors.initials: A
authors.lastname: Kell
authors.affiliation: Department of Biological Chemistry, Weizmann Institute of Sciences, Rehovot, 76100, Israel.
authors.forename: Dominika
authors.initials: D
authors.lastname: Bednarczyk
authors.affiliation: Department of Chemistry, Kansas State University, Manhattan, Kansas, 66506.
authors.forename: Khem
authors.initials: K
authors.lastname: Acharya
authors.affiliation: Department of Chemistry, Kansas State University, Manhattan, Kansas, 66506.
authors.forename: Jinhai
authors.initials: J
authors.lastname: Chen
authors.affiliation: Migal-Galilee Research Institute, Kiryat Shmona, 11016, Israel.
authors.forename: Dror
authors.initials: D
authors.lastname: Noy
authors.affiliation: Department of Chemistry, Kansas State University, Manhattan, Kansas, 66506.|Department of Physics, Kansas State University, Manhattan, Kansas, 66506.
authors.forename: Ryszard
authors.initials: R
authors.lastname: Jankowiak
mesh_terms: D001665:Binding Sites; D002734:Chlorophyll / Q000737:chemistry / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D029686:Lepidium / Q000378:metabolism*; D008958:Models, Molecular; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D013057:Spectrum Analysis; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D010940:Plant Proteins; D014867:Water; D002734:Chlorophyll