Blakeley M P, Mitschler A, Hazemann I, Meilleur F, Myles D A A, Podjarny A
EMBL, 6 Rue Jules Horowitz, BP 181 Cedex 9, 38042, Grenoble, France.
Eur Biophys J. 2006 Sep;35(7):577-83. doi: 10.1007/s00249-006-0064-8. Epub 2006 Apr 19.
Protonation states determination by neutron (2.2 A at room temperature) and X-ray (0.66 A at 100 K) crystallographic studies were compared for a medium size enzyme, human aldose reductase (MW=36 kDa), complexed with its NADP+ coenzyme and a selected inhibitor of therapeutic interest. The neutron resolution could be achieved only with the ab initio fully deuterated protein and the subsequent crystallization in D2O of the complex. We used the largest good-quality crystal (1.00x0.67x0.23 mm, i.e. volume of 0.15 mm3) that we were able to grow so far. Both studies enable the determination of protonation states, with a clear advantage for neutrons in the case of less-ordered atoms (B>5 A2). Hydrogen atoms are best determined by a complementary analysis of the Fourier maps obtained from both methods.
通过中子（室温下为2.2埃）和X射线（100K下为0.66埃）晶体学研究，对一种中等大小的酶——人醛糖还原酶（分子量 = 36 kDa）与其NADP⁺辅酶及一种具有治疗意义的选定抑制剂形成的复合物的质子化状态进行了比较。中子分辨率只能通过从头开始完全氘代的蛋白质以及随后在D₂O中使复合物结晶来实现。我们使用了到目前为止能够生长出的最大的高质量晶体（1.00×0.67×0.23毫米，即体积为0.15立方毫米）。两项研究都能够确定质子化状态，对于无序程度较高的原子（B>5埃²），中子具有明显优势。通过对两种方法获得的傅里叶图进行互补分析，能最好地确定氢原子。
