4dnb
From Proteopedia
|
METHYLATION OF THE ECORI RECOGNITION SITE DOES NOT ALTER DNA CONFORMATION. THE CRYSTAL STRUCTURE OF D(CGCGAM6ATTCGCG) AT 2.0 ANGSTROMS RESOLUTION
Overview
Methylation of nucleic acid bases is known to prevent the cleavage of DNA by restriction endonucleases. The effect on the conformation of the DNA molecule itself and hence its interactions with other DNA binding proteins has been a subject of general interest. To help address this question, we have solved the crystal structure at 2.0 A of the methylated dodecamer, d(CGCGAm6ATTCGCG), which contains the EcoRI recognition sequence and have compared the conformation of the methylated molecule with that of its nonmethylated counterpart. This methylation produces a bulky hydrophobic patch on the floor of the major groove of B-DNA which plays an important role in the mechanism of inhibition of EcoRI restriction activity. However, with the exception of small perturbations in the immediate vicinity of the methyl groups, the structure is virtually unchanged. Given the lack of a conformational change upon methylation, we have extended this thesis of the recognition process to other types of restriction systems and found that different restriction enzymes seem to have their own characteristic protein-DNA interactions. The relative spatial orientations of methylation sites and cleavage sites must play a major role in ordering protein secondary structure elements as well as subunit-subunit interactions along the DNA strand.
About this Structure
4DNB is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Methylation of the EcoRI recognition site does not alter DNA conformation: the crystal structure of d(CGCGAm6ATTCGCG) at 2.0-A resolution., Frederick CA, Quigley GJ, van der Marel GA, van Boom JH, Wang AH, Rich A, J Biol Chem. 1988 Nov 25;263(33):17872-9. PMID:2846582
Page seeded by OCA on Thu Feb 21 19:13:08 2008
