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Updated: Jun 12, 2026

Iterative Optimization of DNA Duplexes for Crystallization of SeqA-DNA Complexes
Published on: November 1, 2012
Crystal structure of MyoD bHLH domain-DNA complex: perspectives on DNA recognition and implications for
P C Ma1, M A Rould, H Weintraub
1Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge 02139.
Abstract:
The crystal structure of a MyoD basic-helix-loop-helix (bHLH) domain-DNA complex has been solved and refined at 2.8 A resolution. This structure proves that bHLH and bHLH-leucine zipper (bHLH-ZIP) proteins are remarkably similar; it helps us understand subtle differences in binding preferences for these proteins; and it has surprising implications for our understanding of transcription. Specifically, Ala-114 and Thr-115, which are required for positive control in the myogenic proteins, are buried at the protein-DNA interface. These residues are not available for direct protein-protein contacts, but they may determine the conformation of Arg-111. Comparisons with Max suggest that the conformation of this arginine, which is different in the two structures, may play an important role in myogenic transcription.
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