title: Analysis of the RNase T1 mediated cleavage of an immobilized gapped heteroduplex via fluorescence correlation spectroscopy.
abstract: We report a new method for studying the activity of hydrolytic enzymes. Fluorescence correlation spectroscopy was used to observe online the hydrolyzation of a rhodamine B-labeled substrate by ribonuclease T1. A gapped heteroduplex substrate - a hybrid of a ribooligonucleotide and two smaller complementary deoxyribooligonucleotides - was immobilized via biotin to a streptavidin-coated surface of a coverslip. The reported method opens the possibility to study the cleavage of small substrates differing only slightly in molecular weight from the enzyme reaction product. The use of fluorescence correlation spectroscopy allows the detection of very low enzyme concentrations (down to 10(-21) mol 0.05 fM of RNase T1, corresponding to about 600 RNase T1 molecules in 0.02 ml).
authors.affiliation: Institut für Biochemie, Fakultät für Biowissenschaften, Pharmazie und Psychologie, Universität Leipzig, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Korn
authors.forename: S
authors.initials: S
authors.lastname: Wennmalm
authors.forename: H H
authors.initials: HH
authors.lastname: Foerster
authors.forename: U
authors.initials: U
authors.lastname: Hahn
authors.forename: R
authors.initials: R
authors.lastname: Rigler
mesh_terms: D001665:Binding Sites; D007700:Kinetics; D008958:Models, Molecular; D009692:Nucleic Acid Heteroduplexes / Q000378:metabolism*; D006163:Ribonuclease T1 / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
chemical_list: D009692:Nucleic Acid Heteroduplexes; D006163:Ribonuclease T1