A specific binding site for neoxanthin in the monomeric antenna proteins CP26 and CP29 of Photosystem II.
The location of the neoxanthin binding site in CP26 and CP29 was investigated by site-directed mutagenesis. The crystallographic structure of LHCII shows that the binding of neoxanthin to the N1 site is stabilised by an H bond with a tyrosine in the lumenal loop. This residue is conserved in CP26 and CP29. Mutation of this tyrosine into phenylalanine induced specific loss of neoxanthin without affecting violaxanthin binding. In contrast to previous proposals, it is thus concluded that also in these minor antenna complexes neoxanthin is accommodated in the N1 site. The characteristics of this binding site in the different antenna complexes are discussed.
Caffarri
Stefano
S
Laboratoire de Génétique et Biophysique des Plante, UMR 6191, CEA-CNRS-Université de la Méditerranée, 163 Av. de Luminy, 13288 Marseille, France.
Passarini
Francesca
F
Bassi
Roberto
R
Croce
Roberta
R
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D061146:Chlorophyll Binding Proteins; D002942:Circular Dichroism; D017124:Conserved Sequence; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D045332:Photosystem II Protein Complex / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D013053:Spectrophotometry; D024341:Xanthophylls / Q000737:chemistry* / Q000378:metabolism*
D029681:Arabidopsis Proteins; C069660:CP29 light harvesting complex; D061146:Chlorophyll Binding Proteins; C490432:LHCB5 protein, Arabidopsis; D045342:Light-Harvesting Protein Complexes; D045332:Photosystem II Protein Complex; D024341:Xanthophylls; C011947:neoxanthin