Spectroscopic and Electrochemical Studies on Structural Change of Plastocyanin and Its Tyrosine 83 Mutants Induced by Interaction with Lysine Peptides
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- 作者：Shun Hirota ; Kozue Hayamizu ; Takashi Okuno ; Mamiko Kishi ; Hideo Iwasaki ; Takao Kondo ; Takashi Hibino ; Teruhiro Takabe ; Takamitsu Kohzuma ; and Osamu Yamauchi
- 刊名：Biochemistry
- 出版年：2000
- 出版时间：May 30, 2000
- 年：2000
- 卷：39
- 期：21
- 页码：6357 - 6364
- 全文大小：192K
- 年卷期：v.39,no.21(May 30, 2000)
- ISSN：1520-4995
文摘
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 byabsorption, 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) 
Cu 3dx2-y2 charge transfer (CT) bandobserved around 600 nm and a stronger intensity for the 460-nm absorption band exhibited strongerintensities for the positive Met Cu 3dx2-y2 and negative His 1 Cu 3dx2-y2 circular dichroism (CD)bands at about 420 and 470 nm, respectively, a lower average 
Cu-S frequency, a smaller 
A
EPR parameter,and a higher redox potential, properties all related to a weaker Cu-S(Cys) bond and a more tetrahedralplanar geometry for the Cu site. Similarly, on oligolysine binding to wild-type and several Tyr83 mutantPCs, a longer absorption maximum for the 600-nm CT band, a stronger intensity for the 460-nm absorptionband, stronger 420-nm positive and 470-nm negative CD bands, and a lower average Cu-S frequencywere 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 tobinding of oligolysine to PC may not be transmitted through the path of Tyr83-Cys84-copper by acation- interaction which is proposed for electron transfer.
Cu 3dx2-y2 charge transfer (CT) bandobserved around 600 nm and a stronger intensity for the 460-nm absorption band exhibited strongerintensities for the positive Met Cu 3dx2-y2 and negative His 1 Cu 3dx2-y2 circular dichroism (CD)bands at about 420 and 470 nm, respectively, a lower average Cu-S frequency, a smaller A EPR parameter,and a higher redox potential, properties all related to a weaker Cu-S(Cys) bond and a more tetrahedralplanar geometry for the Cu site. Similarly, on oligolysine binding to wild-type and several Tyr83 mutantPCs, a longer absorption maximum for the 600-nm CT band, a stronger intensity for the 460-nm absorptionband, stronger 420-nm positive and 470-nm negative CD bands, and a lower average Cu-S frequencywere 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 tobinding of oligolysine to PC may not be transmitted through the path of Tyr83-Cys84-copper by acation- interaction which is proposed for electron transfer.