Henderson S J, Serpersu E H, Gerhardt B S, Bunick G J
Biology Division, Oak Ridge National Laboratory, TN 37831-8077.
Biophys Chem. 1994 Dec;53(1-2):95-104. doi: 10.1016/0301-4622(94)00080-8.
Small-angle neutron scattering (SANS) was used to measure the radius of gyration (Rg) of solutions of phosphoglycerate kinase (PGK) in a variety of substrate environments in D2O. The Rg of 24.0 A was measured for native PGK. A decrease in Rg was observed for the following: 23.7 A for PGK+sulphate; 23.5 A for PGK+ beta, gamma-bidentate Cr(H2O)4ATP (CrATP); 23.3 A for PGK + 3-phospho-D-glycerate (PGA)+CrATP; 22.9 A for PGK+CrATP+sulphate; 22.6 A for PGK+PGA+CrATP+sulphate. The statistical error was about +/- 0.3 A, which is less than systematic effects in this system. These results are consistent with catalysis by a hinge-bending motion of the enzyme. Since CrATP is not hydrolyzed, these results represent the conformational states of the bound substrates in the catalytically relevant ternary complex in the absence of product formation. The second virial coefficient is also measured for this system and this is consistent with that calculated from the protein volume only.
小角中子散射（SANS）被用于测量磷酸甘油酸激酶（PGK）在重水（D₂O）中多种底物环境下溶液的回转半径（Rg）。测得天然PGK的Rg为24.0 Å。观察到以下情况下Rg减小：PGK + 硫酸盐时为23.7 Å；PGK + β,γ - 双齿铬（H₂O）₄ATP（CrATP）时为23.5 Å；PGK + 3 - 磷酸 - D - 甘油酸（PGA）+ CrATP时为23.3 Å；PGK + CrATP + 硫酸盐时为22.9 Å；PGK + PGA + CrATP + 硫酸盐时为22.6 Å。统计误差约为±0.3 Å，这小于该系统中的系统效应。这些结果与酶通过铰链弯曲运动进行催化作用一致。由于CrATP未被水解，这些结果代表了在没有产物形成的情况下催化相关三元复合物中结合底物的构象状态。还测量了该系统的第二维里系数，其与仅根据蛋白质体积计算得出的结果一致。
