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A specific binding site for neoxanthin in the monomeric antenna proteins CP26 and CP29 of Photosystem II
Author(s) -
Caffarri Stefano,
Passarini Francesca,
Bassi Roberto,
Croce Roberta
Publication year - 2007
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2007.08.066
Subject(s) - neoxanthin , chemistry , photosystem ii , binding site , violaxanthin , tyrosine , biophysics , biochemistry , stereochemistry , photochemistry , crystallography , biology , lutein , photosynthesis , zeaxanthin , carotenoid
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.