Binding and wrapping of E. coli single stranded binding protein (SSB) C-terminal tail variants measured using force spectroscopy

Abstract

E. coli single-stranded DNA (ssDNA) binding protein (SSB) is a stable homotetramer that wraps ssDNA in multiple conformations depending on protein concentration and solution conditions. SSB plays an important role in DNA replication and repair and has been utilized in biochemical applications such as increasing PCR specificity and yield. At saturating concentrations, SSB binds to ssDNA in a biphasic manner, in which a rapid contraction of the ssDNA is followed by a slower partial elongation. Subsequent removal of free SSB from solution results in further contraction of the ssDNA, and addition of free SSB again elongates the ssDNA.