Jurgenson Christopher T, Pollard Thomas D
Department of Chemistry and Physics, Delta State University, 1003 West Sunflower Road, Cleveland, MS 38733, USA.
Departments of Molecular, Cellular and Developmental Biology and Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
Acta Crystallogr F Struct Biol Commun. 2015 Sep;71(Pt 9):1161-8. doi: 10.1107/S2053230X15013515. Epub 2015 Aug 25.
Co-crystals of the bovine Arp2/3 complex with the CA motif from N-WASP in two new space groups were analyzed by X-ray diffraction. The crystals in the orthorhombic space group P212121 contained one complex per asymmetric unit, with unit-cell parameters a = 105.48, b = 156.71, c = 177.84 Å, and diffracted to 3.9 Å resolution. The crystals in the tetragonal space group P41 contained two complexes per asymmetric unit, with unit-cell parameters a = b = 149.93, c = 265.91 Å, and diffracted to 5.0 Å resolution. The electron-density maps of both new crystal forms had densities for small segments of subdomains 1 and 2 of Arp2. Both maps had density at the binding site on Arp3 for the C-terminal EWE tripeptide from N-WASP and a binding site proposed for the C motif of N-WASP in the barbed-end groove of Arp2. The map from the tetragonal crystal form had density near the barbed end of Arp3 that may correspond to the C helix of N-WASP. The noise levels and the low resolution of the maps made the assignment of specific molecular structures for any of these CA peptides impossible.
对牛Arp2/3复合物与来自N-WASP的CA基序在两个新空间群中的共晶体进行了X射线衍射分析。正交空间群P212121中的晶体每个不对称单元包含一个复合物，晶胞参数为a = 105.48、b = 156.71、c = 177.84 Å，衍射分辨率为3.9 Å。四方空间群P41中的晶体每个不对称单元包含两个复合物，晶胞参数为a = b = 149.93、c = 265.91 Å，衍射分辨率为5.0 Å。两种新晶体形式的电子密度图在Arp2的亚结构域1和2的小片段处都有密度。两张图在Arp3上N-WASP的C端EWE三肽的结合位点以及Arp2带刺端凹槽中N-WASP的C基序的提议结合位点处都有密度。四方晶体形式的图在Arp3的带刺端附近有密度，可能对应于N-WASP的C螺旋。图的噪声水平和低分辨率使得无法为这些CA肽中的任何一个确定特定的分子结构。
