Fig. 1: Endoribonuclease and exoribonuclease activities of RNase H1 toward the RNA–DNA hybrid.
From: RPA transforms RNase H1 to a bidirectional exoribonuclease for processive RNA–DNA hybrid cleavage
a A schematic of the experimental configuration. A biotinylated RNA–DNA hybrid template is suspended between two streptavidin-coated beads manipulated by two optical traps. Meanwhile, confocal lasers repeatedly scanned along the template. DNA length is expected to increase when the suspended RNA–DNA hybrid is degraded to ssDNA by RNase H1. b The RNA–DNA hybrid template length as a function of time in the presence of 2 nM, 5 nM, and 50 nM RNase H1. c DNA extension rates in nm/s in the presence of 2 (n = 37), 5 (n = 25), and 50 (n = 25) nM RNase H1 under 10 pN. Data are shown as mean ± SEM from Gaussian fittings. d, f Representative kymographs showing the RNA-Cy3 signal (brown) within a 12.3-kbp RNA–DNA hybrid before and after the transportation to the 50 nM or 5 nM RNase H1 channel under a constant force of 10 pN. The corresponding hybrid length of the examined molecule and the Cy3 intensity are shown below the kymographs. The a.u. represents arbitrary units. e, g A representative kymograph showing the association and dissociation of RNase H1-Cy3 (green) with a 7.4-kbp RNA–DNA hybrid before and after the transportation from the buffer channel to the 50 nM or 5 nM RNase H1-Cy3 channel. The corresponding length of the examined molecule and the Cy3 intensity are shown below the kymographs. The a.u. represents arbitrary units. Source data are provided as a Source Data file.
