title: A domain of the manganese-stabilizing protein from Synechococcus elongatus involved in functional binding to photosystem II.
abstract: Site-directed mutagenesis was performed to investigate whether the two protease-sensitive sequences Phe(156)-Gly(163) and Arg(184)-Ser(191), of the manganese-stabilizing protein (MSP) from a thermophilic cyanobacterium, Synechococcus elongatus (Motoki, A., Shimazu, T., Hirano, M., and Katoh, S. (1998) Biochim. Biophys. Acta 1365, 492-502), are involved in functional interaction with photosystem II (PSII). The ability of MSP to bind to its functional site on the PSII complex and to reactivate oxygen evolution was dramatically reduced by the substitution of Arg(152), Asp(158), Lys(160), or Arg(162) with uncharged residues, by insertion of a single residue between Phe(156) and Leu(157), or by deletion of Leu(157). Substitution of each of the four charged residues with an identically charged residue showed that the charges at Asp(158), and possibly Lys(160), are important for the electrostatic interaction with PSII. The reactivating ability was also strongly affected by the alteration of Phe(156) to Leu. Replacement of Lys(188), the only strictly conserved charged residue in the Arg(184)-Ser(191) sequence, by Gln had only a marginal effect on the function of MSP. High affinity binding of MSP to PSII was also affected significantly by mutation at Arg(152), which is located in a region (Val(148)-Arg(152)) strictly conserved among the 14 sequences so far reported. These results imply that the Val(148)-Gly(163) sequence, which is well conserved among MSPs from cyanobacteria to higher plants, is a domain of MSP for functional interaction with PSII.
authors.affiliation: Biological Sciences Department, Toray Research Center Inc., Kamakura 248-8555, Japan. akihiro_motoki@trc.toray.co.jp
authors.forename: Akihiro
authors.initials: A
authors.lastname: Motoki
authors.forename: Mina
authors.initials: M
authors.lastname: Usui
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Shimazu
authors.forename: Masahiko
authors.initials: M
authors.lastname: Hirano
authors.forename: Sakae
authors.initials: S
authors.lastname: Katoh
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D000458:Cyanobacteria / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism*; D045332:Photosystem II Protein Complex; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013056:Spectrophotometry, Ultraviolet
chemical_list: D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D011506:Proteins; C054266:photosystem II manganese-stabilizing protein