Structural and mutational analysis of Escherichia coli AlkB provides insight into substrate specificity and DNA damage searching.

ABSTRACT:

Background

In Escherichia coli, cytotoxic DNA methyl lesions on the N1 position of purines and N3 position of pyrimidines are primarily repaired by the 2-oxoglutarate (2-OG) iron(II) dependent dioxygenase, AlkB. AlkB repairs 1-methyladenine (1-meA) and 3-methylcytosine (3-meC) lesions, but it also repairs 1-methylguanine (1-meG) and 3-methylthymine (3-meT) at a much less efficient rate. How the AlkB enzyme is able to locate and identify methylated bases in ssDNA has remained an open question.

Methodology/principal findings

We determined the crystal structures of the E. coli AlkB protein holoenzyme and the AlkB-ssDNA complex containing a 1-meG lesion. We coupled this to site-directed mutagenesis of amino acids in and around the active site, and tested the effects of these mut

SUBMITTER: Holland PJ 

PROVIDER: S-EPMC2800194 | biostudies-literature | 2010 Jan

REPOSITORIES: biostudies-literature