SNAP-annotated 5mC-DNA-protein interactions: PDB entry 1bsu

PDB-id

1bsu; DSSR-derived features in text and JSON formats; DNAproDB

Class

hydrolase-DNA

Method

X-ray (2.0 Å)

Summary

Structural and energetic origins of indirect readout in site-specific DNA cleavage by a restriction endonuclease

Reference

Martin AM, Sam MD, Reich NO, Perona JJ (1999): "Structural and energetic origins of indirect readout in site-specific DNA cleavage by a restriction endonuclease." Nat.Struct.Biol., 6, 269-277. doi: 10.1038/6707.

Abstract

Specific recognition by EcoRV endonuclease of its cognate, sharply bent GATATC site at the center TA step occurs solely via hydrophobic interaction with thymine methyl groups. Mechanistic kinetic analyses of base analog-substituted DNAs at this position reveal that direct readout provides 5 kcal mol(-1) toward specificity, with an additional 6-10 kcal mol(-1) arising from indirect readout. Crystal structures of several base analog complexes show that the major-groove hydrophobic contacts are crucial to forming required divalent metal-binding sites, and that indirect readout operates in part through the sequence-dependent free-energy cost of unstacking the center base-pair step of the DNA.

• The contacts include paired nucleotides (mostly a G in Watson-Crick G-C pairing) and amino-acids within a 4.5-Å distance cutoff to base atoms of 5mC.
• The structure is oriented in the base reference frame of 5mC, allowing for easy comparison and direct superimposition between entries.
• The black sphere (•) denotes the 5-methyl carbon atom in 5mC.