Title: Direct Comparison of Electron Transfer Properties of Two Distinct Semisynthetic Triads with Non-Protein Based Triad: Unambiguous Experimental Evidences on Protein Matrix Effects
Abstract: Chemistry – A European JournalVolume 6, Issue 11 p. 1907-1916 Full Paper Direct Comparison of Electron Transfer Properties of Two Distinct Semisynthetic Triads with Non-Protein Based Triad: Unambiguous Experimental Evidences on Protein Matrix Effects Yi-Zhen Hu Dr., Yi-Zhen Hu Dr. Department of Chemistry and Biochemistry Graduate School of Engineering Kyushu University, Fukuoka 812-8581 (Japan) Fax: (+81)92-642-3611Search for more papers by this authorHiroshi Takashima, Hiroshi Takashima Department of Chemistry and Biochemistry Graduate School of Engineering Kyushu University, Fukuoka 812-8581 (Japan) Fax: (+81)92-642-3611Search for more papers by this authorShinya Tsukiji, Shinya Tsukiji Department of Chemistry and Biochemistry Graduate School of Engineering Kyushu University, Fukuoka 812-8581 (Japan) Fax: (+81)92-642-3611Search for more papers by this authorSeiji Shinkai Prof., Seiji Shinkai Prof. Department of Chemistry and Biochemistry Graduate School of Engineering Kyushu University, Fukuoka 812-8581 (Japan) Fax: (+81)92-642-3611Search for more papers by this authorTeruyuki Nagamune Prof., Teruyuki Nagamune Prof. Department of Chemistry and Biotechnology Graduate School of Engineering, The University of Tokyo Hongo, Bunkyo-ku, 113-8656 (Japan)Search for more papers by this authorShigero Oishi Prof., Shigero Oishi Prof. Department of Chemistry, School of Science Kitasato University Sagamihara, Kanagawa 228-8520 (Japan)Search for more papers by this authorItaru Hamachi Prof., Itaru Hamachi Prof. [email protected] Department of Chemistry and Biochemistry Graduate School of Engineering Kyushu University, Fukuoka 812-8581 (Japan) Fax: (+81)92-642-3611Search for more papers by this author Yi-Zhen Hu Dr., Yi-Zhen Hu Dr. Department of Chemistry and Biochemistry Graduate School of Engineering Kyushu University, Fukuoka 812-8581 (Japan) Fax: (+81)92-642-3611Search for more papers by this authorHiroshi Takashima, Hiroshi Takashima Department of Chemistry and Biochemistry Graduate School of Engineering Kyushu University, Fukuoka 812-8581 (Japan) Fax: (+81)92-642-3611Search for more papers by this authorShinya Tsukiji, Shinya Tsukiji Department of Chemistry and Biochemistry Graduate School of Engineering Kyushu University, Fukuoka 812-8581 (Japan) Fax: (+81)92-642-3611Search for more papers by this authorSeiji Shinkai Prof., Seiji Shinkai Prof. Department of Chemistry and Biochemistry Graduate School of Engineering Kyushu University, Fukuoka 812-8581 (Japan) Fax: (+81)92-642-3611Search for more papers by this authorTeruyuki Nagamune Prof., Teruyuki Nagamune Prof. Department of Chemistry and Biotechnology Graduate School of Engineering, The University of Tokyo Hongo, Bunkyo-ku, 113-8656 (Japan)Search for more papers by this authorShigero Oishi Prof., Shigero Oishi Prof. Department of Chemistry, School of Science Kitasato University Sagamihara, Kanagawa 228-8520 (Japan)Search for more papers by this authorItaru Hamachi Prof., Itaru Hamachi Prof. [email protected] Department of Chemistry and Biochemistry Graduate School of Engineering Kyushu University, Fukuoka 812-8581 (Japan) Fax: (+81)92-642-3611Search for more papers by this author First published: 14 June 2000 https://doi.org/10.1002/1521-3765(20000602)6:11<1907::AID-CHEM1907>3.0.CO;2-9Citations: 27 Visiting professor of the Institute of Molecular Science at Okazaki (Japan) AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract The role of the protein matrix in electron transfer processes (ET) was investigated using a model system of a heme-based donor (Zn-heme: ZnPP)-sensitizer (Ru2+(bpy)3)-acceptor (cyclic viologen: BXV4+) triad 1. Two semisynthetic systems, in which the triad is incorporated into cytochrome b562 (Cyt-b562) or into myoglobin (Mb) by cofactor reconstitution, were directly compared with the triad 1 without protein matrix. The ET pathways and the lifetimes of the photoinduced charge-separated states (CS states) were remarkably affected by the molecular structure of the three distinct systems. Abstract In order to understand the roles of protein matrix in electron transfer processes (ET) within biological systems, a heme-based donor (Zn-heme: ZnPP)-sensitizer (Ru2+(bpy)3)-acceptor (cyclic viologen: BXV4+) triad 1 was used as a probe molecule. Two semisynthetic systems, Cyt-b562(1) and Mb(1), in which the triad is incorporated into cytochrome b562 (Cyt-b562) or into myoglobin (Mb), were constructed by cofactor reconstitution. These two semisynthetic proteins were compared with the triad itself (i.e., without the protein matrix) using absorption spectroscopy, steady state emission and excitation studies, laser flash photolysis experiments, and molecular modeling. Photoexcitation of the ZnPP moiety of Cyt-b562(1) or Mb(1) leads to a direct ET from the triplet state of ZnPP state (3ZnPP) to BXV4+ to generate a final charge-separated (CS) state, Cyt-b562(Zn+)-Ru2+-BXV3+. or Mb(Zn+)-Ru2+-BXV3+.. On the other hand, direct ET from the excited ZnPP moiety to the BXV4+ moiety is also involved in 1 in the absence of the protein matrix, but the excited state of ZnPP involved is not 3ZnPP, but the singlet excited state (1ZnPP) in this pathway. When the Ru2+(bpy)3 moiety of Cyt-b562(1) or Mb(1) is excited, a stepwise ET relay occurs with the ion-pair, Cyt-b562(Zn)-Ru3+-BXV3+. or Mb(Zn)-Ru3+-BXV3+., as an intermediate, leading to the same final CS state as that generated in the direct ET pathway. The lifetimes of the corresponding final CS states were determined to be 300 ns for 1 in the absence of the protein matrix, 600-900 ns for Cyt-b562(1) and 1.1-18 μs for Mb(1), the values of which are greatly affected by the protein matrix. Molecular modeling study of the three systems consistently explained the differences of their photophysical behavior. Citing Literature Volume6, Issue11June 2, 2000Pages 1907-1916 RelatedInformation
Publication Year: 2000
Publication Date: 2000-06-02
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 33
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