Structure of the higher plant light harvesting complex I: in vivo characterization and structural interdependence of the Lhca proteins.
We have investigated the structure of the higher plant light harvesting complex of photosystem I (LHCI) by analyzing PSI-LHCI particles isolated from a set of Arabidopsis plant lines, each lacking a specific Lhca (Lhca1-4) polypeptide. Functional antenna size measurements support the recent finding that there are four Lhca proteins per PSI in the crystal structure [Ben-Shem, A., Frolow, F., and Nelson, N. (2003) Nature 426, 630-635]. According to HPLC analyses the number of pigment molecules bound within the LHCI is higher than expected from reconstitution studies or analyses of isolated native LHCI. Comparison of the spectra of the particles from the different lines reveals chlorophyll absorption bands peaking at 696, 688, 665, and 655 nm that are not present in isolated PSI or LHCI. These bands presumably originate from "gap" or "linker" pigments that are cooperatively coordinated by the Lhca and/or PSI proteins, which we have tentatively localized in the PSI-LHCI complex.
Klimmek
Frank
F
Department of Plant Physiology, Umeå Plant Science Centre, SE 90189 Umeå, Sweden. frank.klimmek@plantphys.umu.se
Ganeteg
Ulrika
U
Ihalainen
Janne A
JA
van Roon
Henny
H
Jensen
Poul E
PE
Scheller
Henrik V
HV
Dekker
Jan P
JP
Jansson
Stefan
S
D017360:Arabidopsis / Q000737:chemistry / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000378:metabolism; D002151:Calorimetry; D002734:Chlorophyll / Q000378:metabolism; D061146:Chlorophyll Binding Proteins; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry* / Q000378:metabolism; D014975:Lutein / Q000378:metabolism; D045331:Photosystem I Protein Complex / Q000737:chemistry* / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry; D020524:Thylakoids / Q000378:metabolism; D019207:beta Carotene / Q000378:metabolism
D029681:Arabidopsis Proteins; D061146:Chlorophyll Binding Proteins; D045342:Light-Harvesting Protein Complexes; D045331:Photosystem I Protein Complex; D019207:beta Carotene; D002734:Chlorophyll; D014975:Lutein