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The neoxanthin binding site of the major light harvesting complex (LHCII) from higher plants
Author(s) -
Croce Roberta,
Remelli Rosaria,
Varotto Claudio,
Breton Jacques,
Bassi Roberto
Publication year - 1999
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/s0014-5793(99)00907-2
Subject(s) - neoxanthin , helix (gastropod) , polyene , xanthophyll , chemistry , circular dichroism , light harvesting complex , binding site , biophysics , crystallography , biology , biochemistry , lutein , carotenoid , photosynthesis , photosystem ii , zeaxanthin , ecology , snail
The localisation of the xanthophyll neoxanthin within the structure of the major light harvesting complex (LHCII) of higher plants has been investigated by site‐directed mutagenesis and spectroscopic methods. Mutation analysis performed on pigment binding sites in different helix domains leads to selective loss of neoxanthin for mutations on helix C thus localising this pigment between the helix C and helix A/B domains. Recombinant proteins binding two lutein molecules per polypeptide but lacking neoxanthin have been used in order to determine the contribution of neoxanthin to the absorption and linear dichroism spectra. The data were used to derive the orientation of the neoxanthin transition moment, lying in the polyene chain, which was thus determined to form an angle of 57±1.5° with respect to the normal to the membrane plane where the protein is inserted. On the basis of these results we propose a model for the localisation of the carotenoid site in the LHCII structure which is still unresolved.