The EM structure of human DNA polymerase gamma reveals a localized contact between the catalytic and accessory subunits.

ABSTRACT: We used electron microscopy to examine the structure of human DNA pol gamma, the heterotrimeric mtDNA replicase implicated in certain mitochondrial diseases and aging models. Separate analysis of negatively stained preparations of the catalytic subunit, pol gammaA, and of the holoenzyme including a dimeric accessory factor, pol gammaB(2), permitted unambiguous identification of the position of the accessory factor within the holoenzyme. The model explains protection of a partial chymotryptic cleavage site after residue L(549) of pol gammaA upon binding of the accessory subunit. This interaction region is near residue 467 of pol gammaA, where a disease-related mutation has been reported to impair binding of the B subunit. One pol gammaB subunit dominates contacts with the catalytic subunit,

SUBMITTER: Yakubovskaya E 

PROVIDER: S-EPMC2230839 | biostudies-literature | 2007 Oct

REPOSITORIES: biostudies-literature