Spectroscopic and electrochemical studies on structural change of plastocyanin and its tyrosine 83 mutants induced by interaction with lysine peptides

Shun Hirota, Kozue Hayamizu, Takashi Okuno, Mamiko Kishi, Hideo Iwasaki, Takao Kondo, Takashi Hibino, Teruhiro Takabe, Takamitsu Kohzuma, Osamu Yamauchi

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14 Citations (Scopus)

Abstract

Interactions of wild-type and Tyr83 mutant (Y83F, Y83S, Y83L, and Y83H) plastocyanins (PCs) with lysine peptides as models for the PC interacting site of cytochrome f have been studied by absorption, resonance Raman, and electron paramagnetic resonance (EPR) spectroscopies and electrochemical measurements. The spectral and electrochemical properties of PCs corresponded well with each other; species having a longer wavelength maximum for the S(Cys) π → Cu 3d(x2-y2) charge transfer (CT) band observed around 600 nm and a stronger intensity for the 460-nm absorption band exhibited stronger intensities for the positive Met → Cu 3d(x2-y2) and negative His π → Cu 3d(x2-y2) circular dichroism (CD) bands at about 420 and 470 nm, respectively, a lower average v(Cu-S) frequency, a smaller |A(is parallel with)| EPR parameter, and a higher redox potential, properties all related to a weaker Cu-S(Cys) bond and a more tetrahedral planar geometry for the Cu site. Similarly, on oligolysine binding to wild-type and several Tyr83 mutant PCs, a longer absorption maximum for the 600-nm CT band, a stronger intensity for the 460-nm absorption band, stronger 420-nm positive and 470-nm negative CD bands, and a lower average v(Cu-S) frequency were observed, suggesting that PC assumes a slight more tetrahedral geometry on binding of oligolysine. Since changes were observed for both wild-type and Tyr83 mutant PCs, the structural change due to binding of oligolysine to PC may not be transmitted through the path of Tyr83-Cys84-copper by a cation-π interaction which is proposed for electron transfer.

Original languageEnglish
Pages (from-to)6357-6364
Number of pages8
JournalBiochemistry
Volume39
Issue number21
DOIs
Publication statusPublished - 2000 May 30
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry

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    Hirota, S., Hayamizu, K., Okuno, T., Kishi, M., Iwasaki, H., Kondo, T., Hibino, T., Takabe, T., Kohzuma, T., & Yamauchi, O. (2000). Spectroscopic and electrochemical studies on structural change of plastocyanin and its tyrosine 83 mutants induced by interaction with lysine peptides. Biochemistry, 39(21), 6357-6364. https://doi.org/10.1021/bi9929812