Abstract
Lys residues on PsbP responsible for binding with Photosystem II (PSII) remain to be elucidated, although crystal structure of tobacco PsbP has been shown. Previously, we reported using chemical modification of PsbP that the positive charges on Lys residues, especially Lys residues in six domains (Lys11-Lys14, Lys27-Lys38, Lys40, Lys90-Lys96, Lys143-Lys152 and Lys166-Lys174), were important for electrostatic interaction with PSII. In this study, we constructed various spinach PsbP mutants by replacing these Lys with Gly and reconstituted these mutants with PSII to determine the essential lysine residues of PsbP responsible for the binding. The results revealed that Lys residues in Lys11-Lys14, Lys27-Lys38, Lys143-Lys152 and Lys166-Lys174 were essential for the binding. Furthermore, we constructed PsbP mutants by replacing each Lys residue in these domains with Gly and examined their binding abilities. On the basis of these results and crystal structure of PsbP, we will discuss the binding sites of PsbP with PSII.
