  Protein complexes involved in DNA mismatch repair appear to diffuse along
dsDNA in order to locate a hemimethylated incision site via a dissociative
mechanism. Here, we study the probability that these complexes locate a given
target site via a semi-analytic, Monte Carlo calculation that tracks the
association and dissociation of the complexes. We compare such probabilities to
those obtained using a non-dissociative diffusive scan, and determine that for
experimentally observed diffusion constants, search distances, and search
durations $\textit{in vitro}$, there is neither a significant advantage nor
disadvantage associated with the dissociative mechanism in terms of probability
of successful search, and that both search mechanisms are highly efficient for
a majority of hemimethylated site distances. Furthermore, we examine the space
of physically realistic diffusion constants, hemimethylated site distances, and
association lifetimes and determine the regions in which dissociative searching
is more or less efficient than non-dissociative searching. We conclude that the
dissociative search mechanism is advantageous in the majority of the physically
realistic parameter space.

Subcellular Processes;Biological Physics