Differences in the rate of repair of O6-alkylguanines in different sequence contexts by O6-alkylguanine-DNA alkyltransferase.

O6-alkylguanine-DNA alkyltransferase (AGT) repairs O6-alkylguanine residues at different rates depending on the identity of the alkyl group as well as the sequence context. To elucidate the mechanism(s) underlying the differences in rates, we examined the repair of five alkyl groups in three different sequence contexts. The kinact and Km values were determined by measuring the rates of repair of oligodeoxynucleotide duplexes containing the O6-alkylguanine residues with various concentrations of AGT in excess.

Protein stability and surface electrostatics: a charged relationship.

Engineering proteins to withstand a broad range of conditions continues to be a coveted objective, holding the potential to advance biomedicine, industry, and our understanding of disease. One way of achieving this goal lies in elucidating the underlying interactions that define protein stability. It has been shown that the hydrophobic effect, hydrogen bonding, and packing interactions between residues in the protein interior are dominant factors that define protein stability.