title: Asymmetric distribution of biotin labeling on the purple membrane.
abstract: This work examined the biotin modification of bacteriorhodopsin (BR) in the purple membrane (PM). The results of flash kinetic absorption measurements showed that photocycle was maintained in biotinylated BR. Biotinylated BR also maintained its photoelectric activity, as indicated by the photoelectric response of the bilayer lipid membrane (BLM). Atomic force microscopy (AFM) of stretavidiin-bound biotin revealed that biotin molecules covered both surfaces of the, but the amount of biotinylated BR on the extracellular (EC) surface was markedly higher than on the cytoplasmic (CP) surface. Further studies showed that, after reaction with fluorescamine (FL), biotin labeling occurred only on the CP surface. These results are informative for future work on bioconjugation of BR as well as work on oriented assembly and the design of BR-based photoelectric devices.
authors.affiliation: Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Su
authors.forename: Sheng
authors.initials: S
authors.lastname: Zhong
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhang
authors.forename: Kun-Sheng
authors.initials: KS
authors.lastname: Hu
mesh_terms: D001436:Bacteriorhodopsins / Q000737:chemistry / Q000378:metabolism; D001710:Biotin / Q000737:chemistry* / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D005450:Fluorescamine / Q000737:chemistry / Q000378:metabolism; D019617:Halobacterium salinarum / Q000378:metabolism; D007700:Kinetics; D018625:Microscopy, Atomic Force; D010777:Photochemistry; D018717:Purple Membrane / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D019809:Streptavidin / Q000737:chemistry / Q000378:metabolism; D013499:Surface Properties
chemical_list: D005450:Fluorescamine; D001436:Bacteriorhodopsins; D001710:Biotin; D019809:Streptavidin