RESUMO
Pap1 is a fission yeast transcription factor that activates genes related with resistance against staurosporine, a potent inhibitor of protein kinase C, and has been shown to be involved in cell growth, cell cycle, carcinogenesis and differentiation. Pap1 has the bZIP DNA-binding domain but binds to non-consensus DNA sequences for the bZIP motif. Highly ordered crystals of the DNA-binding domain complexed with a DNA fragment that has an ATF/CREB-like non-consensus sequence have been obtained. The crystals grew by the vapor-diffusion technique with polyethylene glycol 6000 and belong to space group R3 with a = b = 240.78, c = 43.85 A. A 2.0 A resolution data set was collected with a cryo-crystallographic technique.
Assuntos
DNA Fúngico/química , Proteínas de Ligação a DNA/química , Proteínas Fúngicas , Conformação Proteica , Schizosaccharomyces/química , Fatores de Transcrição de Zíper de Leucina Básica , Cristalização , Cristalografia por Raios X , DNA Fúngico/metabolismo , Proteínas de Ligação a DNA/isolamento & purificação , Proteínas de Ligação a DNA/metabolismo , Congelamento , Substâncias Macromoleculares , Oligodesoxirribonucleotídeos/química , Oligodesoxirribonucleotídeos/metabolismo , Proteínas Associadas a Pancreatite , Ligação Proteica , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas Recombinantes de Fusão/metabolismo , Proteínas de Schizosaccharomyces pombeRESUMO
Interferon regulatory factors (IRFs) are transcription factors for interferon-related genes, which manifest both antiviral and tumor-suppressor activities and regulate cell growth in response to DNA damage. For the transcription initiation of the interferon-beta gene, IRFs form a macromolecular assembly bound to the promoter DNA, referred to as an enhancesome, together with several other transcription factors and DNA-binding proteins. The three-dimensional structure of IRF-DNA complex would provide insights into the structure and function of the enhancesome. In this study, we crystallized the DNA-binding domain of interferon regulatory factor-2 complexed with a DNA fragment. The crystals reproducibly grew by the vapor diffusion technique with 2-methyl-pentanediol from solutions containing small detergents, such as n-octyl-beta-d-glucoside. Cryocrystallographic experiments showed that crystals belong to space group P212121 with a = 90.66 Å, b = 101.01 Å, c = 171.58 Å and diffract up to 2.8 Å resolution. The absorption measurements of a solution in which the crystals were dissolved indicate that the DNA-binding domain binds to the DNA as a dimer. The calculated values of the solvent contents suggest that the protein-DNA complexes form a multimer in the crystal. These features may reflect the association of the complexes in the enhancesome. Copyright 1998 Academic Press.
