Biochemical Properties of the PsbS Subunit of Photosystem II Either Purified from Chloroplast or Recombinant

The biochemical properties of PsbS protein, a nuclear-encoded Photosystem II subunit involved in the high energy quenching of chlorophyll fluorescence, have been studied using preparations purified from chloroplasts or obtained by overexpression in bacteria. Despite the homology with chlorophylla/b/xanthophyll-binding proteins of the Lhc family, native PsbS protein does not show any detectable ability to bind chlorophylls or carotenoids in conditions in which Lhc proteins maintain full pigment binding. The recombinant protein, when refoldedin vitro in the presence of purified pigments, neither binds chlorophylls nor xanthophylls, differently from the homologous proteins LHCII, CP26, and CP29 PsbS a protein in the from in Lhc homology of PsbS and with the of a homology to the presence of in of the with the of native and recombinant PsbS proteins a homology with CP29 the to involved in The biochemical properties of PsbS protein, a nuclear-encoded Photosystem II subunit involved in the high energy quenching of chlorophyll fluorescence, have been studied using preparations purified from chloroplasts or obtained by overexpression in bacteria. Despite the homology with chlorophylla/b/xanthophyll-binding proteins of the Lhc family, native PsbS protein does not show any detectable ability to bind chlorophylls or carotenoids in conditions in which Lhc proteins maintain full pigment binding. The recombinant protein, when refoldedin vitro in the presence of purified pigments, neither binds chlorophylls nor xanthophylls, differently from the homologous proteins LHCII, CP26, and CP29 PsbS a protein in the from in Lhc homology of PsbS and with the of a homology to the presence of in of the with the of native and recombinant PsbS proteins a homology with CP29 the to involved in II of II CP26, chlorophyll protein of chlorophyll quenching quenching Photosystem II of a of by the or in the the of nuclear-encoded chlorophyll proteins to the Lhc Lhc proteins of in the and which a of the and the of and energy to the Lhc proteins involved in the of energy and and the of the from when the of the The to the of LHCII, which to the of from and to energy to The of from high and the of and the energy quenching the to the of which in the or to the proteins a quenching of chlorophyll to the of to quenching the of and by a binds to in have been the of and a been to The in in in of the of PsbS in to in the of the of the biochemical properties of protein and a homology with proteins in the of the pigment properties of and to PsbS with protein CP29 or the of and quenching have studied the biochemical properties of PsbS purified from or in and in vitro in the presence of PsbS does not bind pigments, or the from involved in pigment in Lhc native and recombinant proteins bind the of a of proteins the quenching the of PsbS in of energy ability of PsbS a protein, a quenching the protein and the energy from the Lhc proteins to involved in energy to of PsbS not a protein, the of quenching the PsbS a to and to proteins the have the from or from overexpression in and in binds to of the Lhc protein a PsbS purified by or by by in the presence of to the a of by and proteins the in which the presence of to by or by by and the of the to a the of and of protein conditions in which PsbS in in a pigment obtained by by a of The of to of the in PsbS a to CP29 from PsbS a protein, the have been in the obtained by when with or in PsbS in the or the of not by by not to PsbS from the of in vitro of proteins the been to pigment proteins from purified from and to the of the protein CP29 and to the of the and of pigment recombinant proteins to the protein purified from the of The purified protein to bind the recombinant protein in vitro been to bind PsbS in and to the in vitro in the presence of purified in conditions in pigment proteins with to to to the of PsbS pigment in with Lhc proteins CP29 and vitro Lhc proteins and in PsbS not with proteins to by in vitro PsbS to the protein purified from by in in a in the of the and in the to the obtained with the with does not pigment binding. by the protein, CP29 which to Lhc in vitro by pigment which with the recombinant protein a to in in the of chlorophyll to PsbS the of homology with Lhc proteins by of and with to show pigment by using the in and the of in a in pigment in Lhc proteins in and proteins the of PsbS with the of CP26, and The and the The involved in the of the in the of and in the of chlorophylls to bind chlorophyll in CP29 and not in the of of the The The not in PsbS not a protein or with of a with to by the and with in the the the and of a with to in the Lhc Lhc proteins pigment PsbS not to in the of with the PsbS in which not The of pigment to PsbS from with to the of of with the PsbS protein, of the in with the not to the to energy and energy the of the PsbS protein by by a by in the in the of the by the of the a in the not from the PsbS of the the of a from the the not the of Lhc of protein have to chlorophyll and binding. the CP29 a protein of from and not pigment and in in in CP29 have been in the of a with the of PsbS to not the of by PsbS a protein to in PsbS to a protein in the by the of of Lhc proteins not been of been to the with a The in the and and CP29 not in the the with by of PsbS does not bind quenching to PsbS and the quenching by the pigment in the not to or proteins involved PsbS quenching of to the of the to The of with in the of PsbS with by of PsbS in preparations obtained with subunit not to and obtained by using the of show not PsbS a of the when to the PsbS in not a subunit Lhc not show of Lhc from PsbS in the and the of CP29 and in CP26, with the of PsbS of in a and CP29 PsbS the of CP26, and Lhc proteins in in by or high the by to PsbS by and PsbS not bind in bind to PsbS and to the of a to chlorophyll by proteins in to a the of the and in in a show the PsbS protein binds the and does not bind or the in the of of the Lhc protein pigment not the of the protein in the of the of PsbS the of to the with and PsbS the PsbS a of a a in proteins to a quenching Photosystem II of a of by the or in the the of nuclear-encoded chlorophyll proteins to the Lhc Lhc proteins of in the and which a of the and the of and energy to the Lhc proteins involved in the of energy and and the of the from when the of the The to the of LHCII, which to the of from and to energy to The of from high and the of and the energy quenching the to the of which in the or to the proteins a quenching of chlorophyll to the of to quenching the of and by a binds to in have been the of and a been to The in in in of the of PsbS in to in the of the of the biochemical properties of protein and a homology with proteins in the of the pigment properties of and to PsbS with protein CP29 or the of and quenching have studied the biochemical properties of PsbS purified from or in and in vitro in the presence of PsbS does not bind pigments, or the from involved in pigment in Lhc native and recombinant proteins bind the of a of proteins the quenching the of PsbS in of energy ability of PsbS a protein, a quenching the protein and the energy from the Lhc proteins to involved in energy to of PsbS not a protein, the of quenching the PsbS a to and to proteins the have the from or from overexpression in and in binds to of the Lhc protein a PsbS purified by or by by in the presence of to the a of by and proteins the in which the presence of to by or by by and the of the to a the of and of protein conditions in which PsbS in in a pigment obtained by by a of The of to of the in PsbS a to CP29 from PsbS a protein, the have been in the obtained by when with or in PsbS in the or the of not by by not to PsbS from the of in vitro of proteins the been to pigment proteins from purified from and to the of the protein CP29 and to the of the and of pigment recombinant proteins to the protein purified from the of The purified protein to bind the recombinant protein in vitro been to bind PsbS in and to the in vitro in the presence of purified in conditions in pigment proteins with to to to the of PsbS pigment in with Lhc proteins CP29 and vitro Lhc proteins and in PsbS not with proteins to by in vitro PsbS to the protein purified from by in in a in the of the and in the to the obtained with the with does not pigment binding. by the protein, CP29 which to Lhc in vitro by pigment which with the recombinant protein a to in in the of chlorophyll to PsbS the of homology with Lhc proteins by of and with to show pigment by using the in and the of in a in pigment in Lhc proteins in and proteins the of PsbS with the of CP26, and The and the The involved in the of the in the of and in the of chlorophylls to bind chlorophyll in CP29 and not in the of of the The The not in PsbS not a protein or with of a with to by the and with in the the the and of a with to in the Lhc Lhc proteins pigment PsbS not to in the of with the PsbS in which not The of pigment to PsbS from with to the of of with the PsbS protein, of the in with the not to the to energy and energy the of the PsbS protein by by a by in the in the of the by the of the a in the not from the PsbS of the the of a from the the not the of Lhc of protein have to chlorophyll and binding. the CP29 a protein of from and not pigment and in in in CP29 have been in the of a with the of PsbS to not the of by PsbS a protein to in PsbS to a protein in the by the of of Lhc proteins not been of been to the with a The in the and and CP29 not in the the with by of PsbS does not bind quenching to PsbS and the quenching by the pigment in the not to or proteins involved PsbS quenching of to the of the to The of with in the of PsbS with by of PsbS in preparations obtained with subunit not to and obtained by using the of show not PsbS a of the when to the PsbS in not a subunit Lhc not show of Lhc from PsbS in the and the of CP29 and in CP26, with the of PsbS of in a and CP29 PsbS the of CP26, and Lhc proteins in in by or high the by to PsbS by and PsbS not bind in bind to PsbS and to the of a to chlorophyll by proteins in to a the of the and in in a show the PsbS protein binds the and does not bind or the in the of of the Lhc protein pigment not the of the protein in the of the of PsbS the of to the with and PsbS the PsbS a of a a in proteins to a quenching the of PsbS in of energy ability of PsbS a protein, a quenching the protein and the energy from the Lhc proteins to involved in energy to of PsbS not a protein, the of quenching the PsbS a to and to proteins the PsbS have the from or from overexpression in and in binds to of the Lhc protein a PsbS purified by or by by in the presence of to the a of by and proteins the in which the presence of to by or by by and the of the to a the of and of protein conditions in which PsbS in in a pigment obtained by by a of The of to of the in PsbS a to CP29 from PsbS a protein, the have been in the obtained by when with or in PsbS in the or the of not by by not to PsbS from the of in vitro of proteins the been to pigment proteins from purified from and to the of the protein CP29 and to the of the and of pigment recombinant proteins to the protein purified from the of The purified protein to bind the recombinant protein in vitro been to bind PsbS in and to the in vitro in the presence of purified in conditions in pigment proteins with to to to the of PsbS pigment in with Lhc proteins CP29 and vitro Lhc proteins and in PsbS not with proteins to by in vitro PsbS to the protein purified from by in in a in the of the and in the to the obtained with the with does not pigment binding. by the protein, CP29 which to Lhc in vitro by pigment which with the recombinant protein a to in in the of chlorophyll to PsbS the of homology with Lhc proteins by of and with to show pigment by using the in and the of in a in pigment in Lhc proteins in and proteins the of PsbS with the of CP26, and The and the The involved in the of the in the of and in the of chlorophylls to bind chlorophyll in CP29 and not in the of of the The The not in PsbS not a protein or with of a with to by the and with in the the the and of a with to in the Lhc Lhc proteins pigment PsbS not to in the of with the PsbS in which not The of pigment to PsbS from with to the of of with the PsbS protein, of the in with the not to the to energy and energy the of the PsbS protein by by a by in the in the of the by the of the a in the not from the PsbS of the the of a from the the not the of Lhc of protein have to chlorophyll and binding. the CP29 a protein of from and not pigment and in in in CP29 have been in the of a with the of PsbS to not the of by PsbS a protein to in PsbS to a protein in the by the of of Lhc proteins not been of been to the with a The in the and and CP29 not in the the with by of PsbS does not bind quenching to PsbS and the quenching by the pigment in the not to or proteins involved PsbS quenching of to the of the to The of with in the of PsbS with by of PsbS in preparations obtained with subunit not to and obtained by using the of show not PsbS a of the when to the PsbS in not a subunit Lhc not show of Lhc from PsbS in the and the of CP29 and in CP26, with the of PsbS of in a and CP29 PsbS the of CP26, and Lhc proteins in in by or high the by to PsbS by and PsbS not bind in bind to PsbS and to the of a to chlorophyll by proteins in to a the of the and in in a show the PsbS protein binds the and does not bind or the in the of of the Lhc protein pigment not the of the protein in the of the of PsbS the of to the with and PsbS the PsbS a of a a in proteins to a quenching PsbS have the from or from overexpression in and in binds to of the Lhc protein a PsbS purified by or by by in the presence of to the a of by and proteins the in which the presence of to by or by by and the of the to a the of and of protein conditions in which PsbS in in a pigment obtained by by a of The of to of the in PsbS a to CP29 from PsbS a protein, the have been in the obtained by when with or in PsbS in the or the of not by by not to PsbS from the of in vitro of proteins the been to pigment proteins from purified from and to the of the protein CP29 and to the of the and of pigment recombinant proteins to the protein purified from the of The purified protein to bind the recombinant protein in vitro been to bind PsbS in and to the in vitro in the presence of purified in conditions in pigment proteins with to to to the of PsbS pigment in with Lhc proteins CP29 and vitro Lhc proteins and in PsbS not with proteins to by in vitro PsbS to the protein purified from by in in a in the of the and in the to the obtained with the with does not pigment binding. by the protein, CP29 which to Lhc in vitro by pigment which with the recombinant protein a to in in the of chlorophyll to PsbS the of homology with Lhc proteins by of and with to show pigment by using the in and the of in a in pigment in Lhc proteins in and proteins the of PsbS with the of CP26, and The and the The involved in the of the in the of and in the of chlorophylls to bind chlorophyll in CP29 and not in the of of the The The not in PsbS not a protein or with of a with to by the and with in the the the and of a with to in the Lhc Lhc proteins pigment PsbS not to in the of with the PsbS in which not The of pigment to PsbS from with to the of of with the PsbS protein, of the in with the not to the to energy and energy the of the PsbS protein by by a by in the in the of the by the of the a in the not from the PsbS of the the of a from the the not the of Lhc of protein have to chlorophyll and binding. the CP29 a protein of from and not pigment and in in in CP29 have been in the of a with the of PsbS to not the of by PsbS a protein to in PsbS to a protein in the by the of of Lhc proteins not been of been to the with a The in the and and CP29 not in the the with by of PsbS does not bind quenching to PsbS and the quenching by the pigment in the not to or proteins involved PsbS quenching of to the of the to The of with in the of PsbS with by of PsbS in preparations obtained with subunit not to and obtained by using the of show not PsbS a of the when to the PsbS in not a subunit Lhc not show of Lhc from PsbS in the and the of CP29 and in CP26, with the of PsbS of in a and CP29 PsbS the of CP26, and Lhc proteins in in by or high the by to PsbS by and PsbS not bind in bind to PsbS and to the of a to chlorophyll by proteins in to a the of the and in in a show the PsbS protein binds the and does not bind or the in the of of the Lhc protein pigment not the of the protein in the of the of PsbS the of to the with and PsbS the PsbS a of a a in proteins to a quenching PsbS have the from or from overexpression in and in binds to of the Lhc protein a PsbS purified by or by by in the presence of to the a of by and proteins the in which the presence of to by or by by and the of the to a the of and of protein conditions in which PsbS in in a pigment obtained by by a of The of to of the in PsbS a to CP29 from PsbS a protein, the have been in the obtained by when with or in PsbS in the or the of not by by not to PsbS from the of in vitro of proteins the been to pigment proteins from purified from and to the of the protein CP29 and to the of the and of pigment recombinant proteins to the protein purified from the of The purified protein to bind the recombinant protein in vitro been to bind PsbS in and to the in vitro in the presence of purified in conditions in pigment proteins with to to to the of PsbS pigment in with Lhc proteins CP29 and vitro Lhc proteins and in PsbS not with proteins to by in vitro PsbS to the protein purified from by in in a in the of the and in the to the obtained with the with does not pigment binding. by the protein, CP29 which to Lhc in vitro by pigment which with the recombinant protein a to in in the of chlorophyll to PsbS the of homology with Lhc proteins by of and with to show pigment by using the in and the of in a in pigment in Lhc proteins in and proteins the of PsbS with the of CP26, and The and the The involved in the of the in the of and in the of chlorophylls to bind chlorophyll in CP29 and not in the of of the The The not in PsbS not a protein or with of a with to by the and with in the the the and of a with to in the Lhc Lhc proteins pigment PsbS not to in the of with the PsbS in which not The of pigment to PsbS from with to the of of with the PsbS protein, of the in with the not to the to energy and energy the of the PsbS protein by by a by in the in the of the by the of the a in the not from the PsbS of the the of a from the have the from or from overexpression in and in binds to of the Lhc protein a PsbS purified by or by by in the presence of to the a of by and proteins the in which the presence of to by or by by and the of the to a the of and of protein conditions in which PsbS in in a pigment obtained by by a of The of to of the in PsbS a to CP29 from PsbS a protein, the have been in the obtained by when with or in PsbS in the or the of not by by not to PsbS from the of in vitro of proteins the been to pigment proteins from purified from and to the of the protein CP29 and to the of the and of pigment recombinant proteins to the protein purified from the of The purified protein to bind the recombinant protein in vitro been to bind PsbS in and to the in vitro in the presence of purified in conditions in pigment proteins with to to to the of PsbS pigment in with Lhc proteins CP29 and vitro Lhc proteins and in PsbS not with proteins to by in vitro PsbS to the protein purified from by in in a in the of the and in the to the obtained with the with does not pigment binding. by the protein, CP29 which to Lhc in vitro by pigment which with the recombinant protein a to in in the of chlorophyll to PsbS the of homology with Lhc proteins by of and with to show pigment by using the in and the of in a in pigment in Lhc proteins in and proteins the of PsbS with the of CP26, and The and the The involved in the of the in the of and in the of chlorophylls to bind chlorophyll in CP29 and not in the of of the The The not in PsbS not a protein or with of a with to by the and with in the the the and of a with to in the Lhc Lhc proteins pigment PsbS not to in the of with the PsbS in which not The of pigment to PsbS from with to the of of with the PsbS protein, of the in with the not to the to energy and energy the of the PsbS protein by by a by in the in the of the by the of the a in the not from the PsbS of the the of a from the the not the of Lhc of protein have to chlorophyll and binding. the CP29 a protein of from and not pigment and in in in CP29 have been in the of a with the of PsbS to not the of by PsbS a protein to in PsbS to a protein in the by the of of Lhc proteins not been of been to the with a The in the and and CP29 not in the the with by of PsbS does not bind quenching to PsbS and the quenching by the pigment in the not to or proteins involved PsbS quenching of to the of the to The of with in the of PsbS with by of PsbS in preparations obtained with subunit not to and obtained by using the of show not PsbS a of the when to the PsbS in not a subunit Lhc not show of Lhc from PsbS in the and the of CP29 and in CP26, with the of PsbS of in a and CP29 PsbS the of CP26, and Lhc proteins in in by or high the by to PsbS by and PsbS not bind in bind to PsbS and to the of a to chlorophyll by proteins in to a the of the and in in a show the PsbS protein binds the and does not bind or the in the of of the Lhc protein pigment not the of the protein in the of the of PsbS the of to the with and PsbS the PsbS a of a a in proteins to a quenching not the of Lhc of protein have to chlorophyll and binding. the CP29 a protein of from and not pigment and in in in CP29 have been in the of a with the of PsbS to not the of by PsbS a protein to in PsbS to a protein in the by the The of of Lhc proteins not been of been to the with a The in the and and CP29 not in the the with by of PsbS does not bind quenching to PsbS and the quenching by the pigment in the not to or proteins involved PsbS quenching of to the of the to The of with in the of PsbS with by of PsbS in preparations obtained with subunit not to and obtained by using the of show not PsbS a of the when to the PsbS in not a subunit Lhc not show of Lhc from PsbS in the and the of CP29 and in CP26, with the of PsbS of in a and CP29 PsbS the of CP26, and Lhc proteins in in by or high the by to PsbS by and PsbS not bind in bind to PsbS and to the of a to chlorophyll by proteins in to a the of the and in in a show the PsbS protein binds the and does not bind or the in the of of the Lhc protein pigment not the of the protein in the of the of PsbS the of to the with and PsbS the PsbS a of a a in proteins to a quenching of the of the and and