MBI Publications

MBI Publications for Ajeet Sharma (1)

  • A. Sharma and D. Chowdhury
    Error correction during DNA replication
    Physical Review EVol. 86 No. 011913 (2012)


    DNA polymerase (DNAP) is a dual-purpose enzyme that plays two opposite roles in two different situations
    during DNA replication. It plays its a normal role as a polymerase catalyzing the elongation of a new DNA
    molecule by adding a monomer. However, it can switch to the role of an exonuclease and shorten the same
    DNA by cleavage of the last incorporated monomer from the nascent DNA. Just as misincorporated nucleotides
    can escape exonuclease causing a replication error, the correct nucleotide may get sacrificed unnecessarily by
    erroneous cleavage. The interplay of polymerase and exonuclease activities of a DNAP is explored here by
    developing a minimal stochastic kinetic model of DNA replication. Exact analytical expressions are derived for
    a few key statistical distributions; these characterize the temporal patterns in the mechanical stepping and the
    chemical (cleavage) reaction. The Michaelis-Menten-like analytical expression derived for the average rates of
    these two processes not only demonstrate the effects of their coupling, but are also utilized to measure the extent
    of replication error and erroneous cleavage.

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