Raghunathan S, Ricard C S, Lohman T M, Waksman G
Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
Proc Natl Acad Sci U S A. 1997 Jun 24;94(13):6652-7. doi: 10.1073/pnas.94.13.6652.
The crystal structure of the tetrameric DNA-binding domain of the single-stranded DNA binding protein from Escherichia coli was determined at a resolution of 2.9 A using multiwavelength anomalous dispersion. Each monomer in the tetramer is topologically similar to an oligomer-binding fold. Two monomers each contribute three beta-strands to a single six-stranded beta-sheet to form a dimer. Two dimer-dimer interfaces are observed within the crystal. One of these stabilizes the tetramer in solution. The other interface promotes a superhelical structure within the crystal that may reflect tetramer-tetramer interactions involved in the positive cooperative binding of the single-stranded DNA-binding protein to single-stranded DNA.
利用多波长反常散射技术,以2.9埃的分辨率测定了来自大肠杆菌的单链DNA结合蛋白四聚体DNA结合结构域的晶体结构。四聚体中的每个单体在拓扑结构上类似于一个寡聚体结合折叠。两个单体各为一个单一的六链β-折叠贡献三条β-链,形成一个二聚体。在晶体内观察到两个二聚体-二聚体界面。其中一个在溶液中稳定四聚体。另一个界面促进晶体内的超螺旋结构,这可能反映了单链DNA结合蛋白与单链DNA的正协同结合中涉及的四聚体-四聚体相互作用。