Recombinant humanO6-alkylguanine-DNA alkyltransferase induces conformational change in bound DNA

Abstract
Circular dichroism, and steady‐state and time‐resolved fluorescence spectroscopy were used to compare the native recombinant human DNA repair protein O 6‐alkylguanine‐DNA alkyltransferase (AGT) with AGT bound to ds‐DNA. Contrary to fluorescence, analysis of the far‐UV CD spectra indicated a conformational change of AGT upon binding to DNA: its α‐helical content is increased by ∼12%. Analysis of near‐UV CD spectra revealed that DNA was also affected, probably being separated into single strands locally.