TY - JOUR
T1 - Ultrafast redistribution of E. coli SSB along Long single-stranded DNA via intersegment transfer
AU - Lee, Kyung Suk
AU - Marciel, Amanda B.
AU - Kozlov, Alexander G.
AU - Schroeder, Charles M.
AU - Lohman, Timothy M.
AU - Ha, Taekjip
N1 - Funding Information:
This work was supported by the US National Institutes of Health ( GM065367 and RR025341 to T.H. and GM030498 to T.M.L.) and by the National Science Foundation ( 0822613 and 0646550 to T.H.). T.H. is an investigator in the Howard Hughes Medical Institute.
PY - 2014/6/26
Y1 - 2014/6/26
N2 - Single-stranded DNA binding proteins (SSBs) selectively bind single-stranded DNA (ssDNA) and facilitate recruitment of additional proteins and enzymes to their sites of action on DNA. SSB can also locally diffuse on ssDNA, which allows it to quickly reposition itself while remaining bound to ssDNA. In this work, we used a hybrid instrument that combines single-molecule fluorescence and force spectroscopy to directly visualize the movement of Escherichia coli SSB on long polymeric ssDNA. Long ssDNA was synthesized without secondary structure that can hinder quantitative analysis of SSB movement. The apparent diffusion coefficient of E. coli SSB thus determined ranged from 70,000 to 170,000 nt2/s, which is at least 600 times higher than that determined from SSB diffusion on short ssDNA oligomers, and is within the range of values reported for protein diffusion on double-stranded DNA. Our work suggests that SSB can also migrate via a long-range intersegment transfer on long ssDNA. The force dependence of SSB movement on ssDNA further supports this interpretation.
AB - Single-stranded DNA binding proteins (SSBs) selectively bind single-stranded DNA (ssDNA) and facilitate recruitment of additional proteins and enzymes to their sites of action on DNA. SSB can also locally diffuse on ssDNA, which allows it to quickly reposition itself while remaining bound to ssDNA. In this work, we used a hybrid instrument that combines single-molecule fluorescence and force spectroscopy to directly visualize the movement of Escherichia coli SSB on long polymeric ssDNA. Long ssDNA was synthesized without secondary structure that can hinder quantitative analysis of SSB movement. The apparent diffusion coefficient of E. coli SSB thus determined ranged from 70,000 to 170,000 nt2/s, which is at least 600 times higher than that determined from SSB diffusion on short ssDNA oligomers, and is within the range of values reported for protein diffusion on double-stranded DNA. Our work suggests that SSB can also migrate via a long-range intersegment transfer on long ssDNA. The force dependence of SSB movement on ssDNA further supports this interpretation.
KW - optical tweezer
KW - single-stranded DNA
KW - single-stranded DNA binding protein
UR - http://www.scopus.com/inward/record.url?scp=84901768289&partnerID=8YFLogxK
U2 - 10.1016/j.jmb.2014.04.023
DO - 10.1016/j.jmb.2014.04.023
M3 - Article
C2 - 24792418
AN - SCOPUS:84901768289
SN - 0022-2836
VL - 426
SP - 2413
EP - 2421
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
IS - 13
ER -