1.
J Biol Chem
; 284(34): 22690-6, 2009 Aug 21.
Article
in English
| MEDLINE
| ID: mdl-19497854
ABSTRACT
Enzymes that modify DNA are faced with significant challenges in specificity for both substrate binding and catalysis. We describe how single hydrogen bonds between M.HhaI, a DNA cytosine methyltransferase, and its DNA substrate regulate the positioning of a peptide loop which is approximately 28 A away. Stopped-flow fluorescence measurements of a tryptophan inserted into the loop provide real-time observations of conformational rearrangements. These long-range interactions that correlate with substrate binding and critically, enzyme turnover, will have broad application to enzyme specificity and drug design for this medically relevant class of enzymes.