Liu S, Fedorov A A, Pollard T D, Lattman E E, Almo S C, Magnus K A
Department of Biochemistry, Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio, 44106-4935, USA.
J Struct Biol. 1998 Sep;123(1):22-9. doi: 10.1006/jsbi.1998.4009.
Profilin-I from Acanthamoeba castellanii is a 13-kDa protein that binds actin and poly-l-proline. The native protein has been crystallized in two different but closely related forms. The second form proved more amenable to three-dimensional structural determination using heavy-atom isomorphous methods to obtain crystallographic phase information. We used the second crystal structure as a test molecule in the molecular replacement procedure to determine the structure of the first crystal form of profilin-I. More residues participate in crystal lattice contacts in the first crystal form than in the second. The two crystal forms differ significantly in the C-terminal helix that interacts with actin and in the loop preceding this helix. Coordinates of some main chain atoms here differ by about 1.0 A, and side chain atoms differ by more than 2.0 A.
来自卡氏棘阿米巴的肌动蛋白结合蛋白I是一种13 kDa的蛋白质，可结合肌动蛋白和聚-L-脯氨酸。天然蛋白已结晶为两种不同但密切相关的形式。第二种形式被证明更适合使用重原子同晶型方法来获得晶体学相位信息，以进行三维结构测定。我们在分子置换过程中使用第二种晶体结构作为测试分子来确定肌动蛋白结合蛋白I第一种晶体形式的结构。第一种晶体形式中参与晶格接触的残基比第二种更多。两种晶体形式在与肌动蛋白相互作用的C端螺旋以及该螺旋之前的环中存在显著差异。此处一些主链原子的坐标相差约1.0 Å，侧链原子相差超过2.0 Å。
