Direct measurements of the stabilization of single-stranded DNA under tension by single-stranded binding proteins.
The unzipping and rezipping of a double-stranded DNA molecule is carried out in the presence of two single-stranded binding proteins T4 gp32 and E. Coli SSB protein to determine the effect of the proteins on the stability of single- and double-stranded DNA. The proteins do not have a significant effect on unzipping, indicating that the two proteins do not destabilize the double-stranded DNA; however, both proteins inhibit rezipping. At protein concentrations where the rezipping force response is saturated, E. Coli SSB protein reduces the rezipping force to 5.5+/-1.5 pN , while T4 gp32 completely blocks rezipping on the time scale of the experiment.
Hatch
K
K
Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
Danilowicz
C
C
Coljee
V
V
Prentiss
M
M
D001703:Biophysics / Q000295:instrumentation / Q000379:methods*; D004277:DNA, Single-Stranded / Q000737:chemistry*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000378:metabolism; D015233:Models, Statistical; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry; D012107:Research Design; D013314:Stress, Mechanical; D013718:Tensile Strength; D014764:Viral Proteins / Q000378:metabolism
D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D011506:Proteins; C476430:SSB protein, E coli; D014764:Viral Proteins; C060035:gp32 protein, Enterobacteria phage T4