Additivity in the Contribution to Herbicide Binding of Amino Acid Residues in the D1 Protein of Photosystem II

The folding through the membrane of the plastoquinone and herbicide binding protein subunits of photosystem II and the topology of the binding niche for plastoquinone and herbicides is described. The model is based on the homology in amino acid sequence and folding prediction from the hydropathy analysis of the D-1 and D-2 subunits of photosystem II to the reaction center polypeptides L and M of the bacterial reaction center. It incorporates the amino acid changes in the D-1 polypeptide in herbicide tolerant plants and those indicated by chemical tagging to be involved in Qв binding. It proposes homologous amino acids in the D-1/D-2 polypeptides to those indicated by the X-ray structure of the bacterial reaction center to be involved in Fe-, quinone- and reaction center chlorophyll-binding. The different chemical compounds known to interfere with Qв function are grouped into two families depending on their orientation in the Qв binding niche.

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A Contact Site between the Two Reaction Center Polypeptides of Photosystem II Is Involved in Photoinhibition

Zeitschrift für Naturforschung C ◽

10.1515/znc-1991-7-809 ◽

1991 ◽

Vol 46 (7-8) ◽

pp. 557-562 ◽

Cited By ~ 36

Author(s):

A. Trebst

Keyword(s):

Amino Acid ◽

Photosystem Ii ◽

Reaction Center ◽

Binding Sites ◽

Cleavage Site ◽

Amino Acid Sequences ◽

Contact Site ◽

Quinone Binding ◽

Herbicide Binding ◽

Sensitive Site

Abstract A new contact site between the two reaction center polypeptides D 1 and D 2 of photosystem II close to arg 238 and arg 234 respectively is proposed. The amino acid sequences involved are between the 4 th transmembrane and a connecting parallel helix. The sequence includes a tryp sin sensitive site in both polypeptides, the likely cleavage site in the rapid turnover of the D 1 polypeptide and part of the herbicide binding site. The contact site is oriented towards both quinone binding sites Q A and Q B. A folding of the backbone of the amino acid sequences involved is proposed.

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Identification of Oxidized Amino Acid Residues in the Vicinity of the Mn4CaO5Cluster of Photosystem II: Implications for the Identification of Oxygen Channels within the Photosystem

Biochemistry ◽

10.1021/bi300650n ◽

2012 ◽

Vol 51 (32) ◽

pp. 6371-6377 ◽

Cited By ~ 34

Author(s):

Laurie K. Frankel ◽

Larry Sallans ◽

Patrick A. Limbach ◽

Terry M. Bricker

Keyword(s):

Amino Acid ◽

Photosystem Ii ◽

Amino Acid Residues

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Amino acid residues that modulate the properties of tyrosine YZ and the manganese cluster in the water oxidizing complex of photosystem II

Biochimica et Biophysica Acta (BBA) - Bioenergetics ◽

10.1016/s0005-2728(00)00221-8 ◽

2001 ◽

Vol 1503 (1-2) ◽

pp. 164-186 ◽

Cited By ~ 127

Author(s):

Richard J Debus

Keyword(s):

Amino Acid ◽

Photosystem Ii ◽

Amino Acid Residues ◽

Manganese Cluster ◽

Water Oxidizing Complex

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Structure - function analysis of photosystem II subunit S (PsbS) in vivo

Functional Plant Biology ◽

10.1071/fp02065 ◽

2002 ◽

Vol 29 (10) ◽

pp. 1131 ◽

Cited By ~ 98

Author(s):

Xiao-Ping Li ◽

Alba Phippard ◽

Jae Pasari ◽

Krishna K. Niyogi

Keyword(s):

Amino Acid ◽

Photosystem Ii ◽

Function Analysis ◽

Amino Acid Sequences ◽

Forward Genetics ◽

Photochemical Quenching ◽

Amino Acid Residues ◽

The Stability ◽

Psbs Gene

In land plants, photosystem II subunit S (PsbS) plays a key role in xanthophyll- and pH-dependent non-photochemical quenching (qE) of excess absorbed light energy. Arabidopsis thaliana (L.) Heynh. npq4 mutants are defective in the psbS gene and have impaired qE. Exactly how the PsbS protein is involved in qE is unclear, but it has been proposed that PsbS binds H+ and/or de-epoxidized xanthophylls in excess light as part of the qE mechanism. To identify amino acid residues that are important for PsbS function, we sequenced the psbS gene from eight npq4 point mutant alleles isolated by forward genetics screening, including two new alleles. In the four transmembrane helices of PsbS, several amino acid residues were found to affect the stability and/or function of the protein. By comparing the predicted amino acid sequences of PsbS from several plant species and studying the proposed topological structure of PsbS, eight possible H+-binding amino acid residues on the lumenal side of the protein were identified and then altered by site-directed mutagenesis in vitro. The mutant psbS genes were transformed into npq4-1, a psbS deletion mutant, to test the stability and function of the mutant PsbS proteins in�vivo. The results demonstrate that two conserved, protonatable amino acids, E122 and E226, are especially critical for the function of PsbS.

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