title: Differentiating the orientations of photosynthetic reaction centers on Au electrodes linked by different bifunctional reagents.
abstract: The photosynthetic reaction center (RC) composite film was fabricated by self-assembled monolayers (SAMs) on the Au electrode with two different bifunctional reagents, 4-aminothiophenol (ATP) and 2-mercaptoethylamine (MEA), respectively. The square wave voltametry (SWV), bulk electrolysis and photocurrent test were employed for characterizing the composite film. The dramatic different electrochemical characteristics were observed for the two types of films, which strongly suggested an orientational difference for RC arising from the structural difference between the two bifunctional reagents. For RC-MEA film, three redox peaks which implying electron transfer (ET) between the primary donor (P) and the bacteriopheophytin (Bphe) were observed. While for RC-ATP film, two redox peaks implying ET between the nonheme iron and the primary quinone (Q(A)) were observed. The ET behavior driven by electric field also supported the result that the RC could be linked to the electrode at different sites. The site-specific immobilization approach reported here supplies a method to differentiate the protein orientation.
authors.affiliation: Chemistry Department, Fudan University, Shanghai 200433, People's Republic of China.
authors.forename: Jiequan
authors.initials: J
authors.lastname: Zhao
authors.forename: Yonglong
authors.initials: Y
authors.lastname: Zou
authors.forename: Baohong
authors.initials: B
authors.lastname: Liu
authors.forename: Chunhe
authors.initials: C
authors.lastname: Xu
authors.forename: Jilie
authors.initials: J
authors.lastname: Kong
mesh_terms: D000814:Aniline Compounds; D015374:Biosensing Techniques; D003432:Cross-Linking Reagents; D003543:Cysteamine; D004566:Electrodes; D004579:Electron Transport; D006046:Gold; D010084:Oxidation-Reduction; D010674:Pheophytins / Q000737:chemistry; D010777:Photochemistry; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D013438:Sulfhydryl Compounds
chemical_list: D000814:Aniline Compounds; D003432:Cross-Linking Reagents; D010674:Pheophytins; D045322:Photosynthetic Reaction Center Complex Proteins; D013438:Sulfhydryl Compounds; C006678:bacteriopheophytin; D003543:Cysteamine; D006046:Gold; C064316:4-aminothiophenol