title: Structural mapping of cysteine-63 of the chloroplast ATP synthase beta subunit.
abstract: The single sulfhydryl residue (cysteine-63) of the beta subunit of the chloroplast ATP synthase F1 (CF1) was accessible to labeling reagents only after removal of the beta subunit from the enzyme complex. This suggests that cysteine-63 may be located at an interface between the beta and the alpha subunits of CF1, although alternative explanations such as a conformational change in beta brought about by its release from CF1 cannot be ruled out. Cysteine-63 was specifically labeled with [(diethylamino)methylcoumarinyl]-maleimide, and the distance between this site and trinitrophenyl-ADP at the nucleotide binding site on beta was mapped using fluorescence resonance energy transfer. Cysteine-63 is located in a hydrophobic pocket, 42 A away from the nucleotide binding site on beta.
authors.affiliation: Department of Biochemistry, University of Kansas, Lawrence 66045.
authors.forename: K K
authors.initials: KK
authors.lastname: Colvert
authors.forename: D A
authors.initials: DA
authors.lastname: Mills
authors.forename: M L
authors.initials: ML
authors.lastname: Richter
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002736:Chloroplasts / Q000201:enzymology*; D003374:Coumarins; D003545:Cysteine / Q000737:chemistry*; D004735:Energy Transfer; D019793:Fluorescein; D005452:Fluoresceins; D005454:Fluorescence Polarization; D005456:Fluorescent Dyes; D007700:Kinetics; D008301:Maleimides; D008969:Molecular Sequence Data; D010944:Plants / Q000201:enzymology; D011487:Protein Conformation; D006180:Proton-Translocating ATPases / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D003374:Coumarins; D005452:Fluoresceins; D005456:Fluorescent Dyes; D008301:Maleimides; C074193:N-(4-(7-(diethylamino)-4-methylcoumarin-3-yl))maleimide; D006180:Proton-Translocating ATPases; D003545:Cysteine; D019793:Fluorescein