title: Crystal structure of MyoD bHLH domain-DNA complex: perspectives on DNA recognition and implications for transcriptional activation.
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.
authors.affiliation: Department of Biology, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge 02139.
authors.forename: P C
authors.initials: PC
authors.lastname: Ma
authors.forename: M A
authors.initials: MA
authors.lastname: Rould
authors.forename: H
authors.initials: H
authors.lastname: Weintraub
authors.forename: C O
authors.initials: CO
authors.lastname: Pabo
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D050976:Basic-Leucine Zipper Transcription Factors; D001665:Binding Sites; D003196:Computer Graphics; D003460:Crystallization; D018360:Crystallography, X-Ray; D004268:DNA-Binding Proteins / Q000737:chemistry; D018257:Helix-Loop-Helix Motifs; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017570:MyoD Protein / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D009690:Nucleic Acid Conformation; D010455:Peptides / Q000138:chemical synthesis / Q000302:isolation & purification; D011119:Polynucleotides / Q000138:chemical synthesis / Q000378:metabolism*; D011487:Protein Conformation; D016415:Sequence Alignment; D014157:Transcription Factors
chemical_list: D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; C067850:Myc associated factor X; D017570:MyoD Protein; D010455:Peptides; D011119:Polynucleotides; D014157:Transcription Factors