BECAS
INCICCO Juan JeremÍas
congresos y reuniones científicas
Título:
Kinetic analysis of the interaction between dengue virus NS3 helicase and ssRNA
Autor/es:
J. JEREMÍAS INCICCO; LEILA A. CABABIE; LEOPOLDO G. GEBHARD; ANDREA V. GAMARNIK; RODOLFO M. GONZÁLEZ-LEBRERO; SERGIO B. KAUFMAN
Lugar:
Steamboat, Colorado
Reunión:
Congreso; Helicases and Nucleic-Acid Based Machines: From Mechanism to Insight into Disease; 2015
Institución organizadora:
FASEB
Resumen:
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Dengue
virus nonstructural protein 3 (NS3) is a molecular motor protein that
unwinds duplex RNA driven by the free energy derived from the
hydrolysis of nucleoside triphosphates.
In
previous studies we examined the interaction of NS3h with ssRNA under
equilibrium conditions and we found that the interaction is
characterized by minimum and occluded site sizes both of 10
nucleotides. In this presentation we show results from the study of
the kinetic mechanism of this interaction obtained from stopped-flow
experiments. A series of 5?-fluorescein-labeled oligonucleotides of
different lengths (11 to 21 nucleotides) with a repetitive sequence
of five nucleotides (AGUUG) were employed and the binding time
courses to the NS3h was monitored by the fluorescence increase
observed upon excitation at 495 nm. Reaction were carried out at 25ºC
in buffer B (MOPS 25 mM, pH 6.4, KCl 100 mM (total K+),
EDTA 0.50 mM, MgCl2 2.0 mM).
The binding time courses observed under pseudofirst order conditions
required a minimum of three exponential terms for an adequate fit. A
three-steps kinetic model was able to describe the experimental time
courses and provided best-fitting estimates of the rate constants for
each oligonucleotide tested.