Three-dimensional model of zeaxanthin binding PsbS protein associated with nonphotochemical quenching of excess quanta of light energy absorbed by the photosynthetic apparatus.
A three-dimensional model of the PsbS protein was built with the help of homology-modeling methods. This protein is also known as CP22 and is associated with the protection of photosystem II of thylakoid from excess quanta of light energy absorbed by the photosynthetic apparatus. PsbS is reported to bind two molecules of zeaxanthin at low pH (<5.0) and is believed to be essential for rapid nonphotochemical quenching (qE) of chlorophyll a fluorescence in photosystem II. An attempt was made to explain the pH modulation of the conformation of protein through salt-bridges Glu(-)(122)-Lys(+)(113) and Glu(-)(226)-Lys(+)(217). Binding of two molecules of zeaxanthin in the three-dimensional model of PsbS is postulated. The molecular mechanism of photoprotection by PsbS is explained through the model.
P.G. Department of Chemistry, Government College, Sundargarh, Orissa, 770002, India.
Prafulla K
PK
Haripal
Hemant K
HK
Raval
Mukesh K
MK
Raval
Rakesh M
RM
Rawal
Basanti
B
Biswal
Udaya C
UC
Biswal
D029681:Arabidopsis Proteins / Q000737:chemistry; D001665:Binding Sites; D006863:Hydrogen-Ion Concentration; D008027:Light; D008958:Models, Molecular; D017785:Photons; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D045332:Photosystem II Protein Complex / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D055672:Static Electricity; D020524:Thylakoids / Q000737:chemistry; D024341:Xanthophylls / Q000737:chemistry*; D065146:Zeaxanthins
D029681:Arabidopsis Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D024341:Xanthophylls; D065146:Zeaxanthins