SNAP output for PDB entry 1le8 [SNAP web server]

PDB-id

1le8; SNAP-derived features in text and JSON formats; DNAproDB

Class

transcription-DNA

Method

X-ray (2.3 Å)

Summary

Crystal structure of the mata1-matalpha2-3a heterodimer bound to DNA complex

Reference

Ke A, Mathias JR, Vershon AK, Wolberger C (2002): "Structural and Thermodynamic Characterization of the DNA Binding Properties of a Triple Alanine Mutant of MATalpha2." Structure, 10, 961-971. doi: 10.1016/S0969-2126(02)00790-6.

Abstract

Triply mutated MATalpha2 protein, alpha2-3A, in which all three major groove-contacting residues are mutated to alanine, is defective in binding DNA alone or in complex with Mcm1 yet binds with MATa1 with near wild-type affinity and specificity. To gain insight into this unexpected behavior, we determined the crystal structure of the a1/alpha2-3A/DNA complex. The structure shows that the triple mutation causes a collapse of the alpha2-3A/DNA interface that results in a reorganized set of alpha2-3A/DNA contacts, thereby enabling the mutant protein to recognize the wild-type DNA sequence. Isothermal titration calorimetry measurements reveal that a much more favorable entropic component stabilizes the a1/alpha2-3A/DNA complex than the alpha2-3A/DNA complex. The combined structural and thermodynamic studies provide an explanation of how partner proteins influence the sequence specificity of a DNA binding protein.