title: Cloning, purification and preliminary X-ray data analysis of the human ID2 homodimer.
abstract: The ID proteins are named for their role as inhibitors of DNA binding and differentiation. They contain a helix-loop-helix (HLH) domain but lack a basic DNA-binding domain. In complex with basic HLH (bHLH) transcription factors, gene expression is regulated by DNA-binding inactivation. Although the HLH domain is highly conserved and shares a similar topology, the IDs preferentially bind class I bHLH-group members such as E47 (TCF3) but not the class III bHLH member Myc. A structure of an ID protein could potentially shed light on its mechanism. Owing to their short half-lives in vivo and reported in vitro instability, this paper describes the strategies that went into expressing sufficient soluble and stable ID2 to finally obtain diffraction-quality crystals. A 2.1 Å resolution data set was collected from a crystal belonging to space group P3(1)21 with unit-cell parameters a=b=51.622, c=111.474 Å, α=β=90, γ=120° that was obtained by hanging-drop vapour diffusion in a precipitant solution consisting of 0.1 M MES pH 6.5, 2.0 M potassium acetate. The solvent content was consistent with the presence of one or two molecules in the asymmetric unit.
authors.affiliation: Laboratory for Structural Biochemistry, Genome Institute of Singapore, Genome, 60 Biopolis Street, Singapore 138672, Singapore.
authors.forename: Marie V
authors.initials: MV
authors.lastname: Wong
authors.forename: Paaventhan
authors.initials: P
authors.lastname: Palasingam
authors.forename: Prasanna R
authors.initials: PR
authors.lastname: Kolatkar
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001667:Binding, Competitive; D002846:Chromatography, Affinity; D003001:Cloning, Molecular; D017124:Conserved Sequence; D003460:Crystallization; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry; D006801:Humans; D051797:Inhibitor of Differentiation Protein 2 / Q000737:chemistry* / Q000302:isolation & purification; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D055550:Protein Stability; D020836:Protein Structure, Quaternary
chemical_list: C497450:ID2 protein, human; D051797:Inhibitor of Differentiation Protein 2; D004247:DNA