Schmitke J L, Stern L J, Klibanov A M
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA.
Biochem Biophys Res Commun. 1998 Jul 20;248(2):273-7. doi: 10.1006/bbrc.1998.8937.
The X-ray crystal structures of the protease subtilisin Carlsberg in 40% acetonitrile and in 20% dioxane have been determined to at least 2.3 A resolution, and their solvent binding patterns have been compared to those observed in the neat organic solvents. The structures of the protein in the two aqueous-organic mixtures are essentially the same as in pure water, acetonitrile, and dioxane. Interestingly, the enzyme-bound organic solvent molecules tend to congregate in the active site. Three of the five bound acetonitrile molecules observed in the structure of subtilisin in 40% acetonitrile are situated in the enzyme active site, as is the single enzyme-bound dioxane molecule observed in 20% dioxane (whose location is distinct from that of any bound acetonitrile molecule). Furthermore, the organic solvent molecules detected in the enzyme active site in the aqueous-organic mixtures are in the same locations as in the structures in the corresponding neat organic solvents.
已测定了枯草杆菌蛋白酶卡尔伯格在40%乙腈和20%二氧六环中的X射线晶体结构，分辨率至少为2.3埃，并将其溶剂结合模式与在纯有机溶剂中观察到的模式进行了比较。该蛋白质在两种水-有机混合物中的结构与在纯水、乙腈和二氧六环中的基本相同。有趣的是，与酶结合的有机溶剂分子倾向于聚集在活性位点。在40%乙腈中枯草杆菌蛋白酶结构中观察到的五个结合乙腈分子中有三个位于酶活性位点，在20%二氧六环中观察到的单个与酶结合的二氧六环分子也是如此（其位置与任何结合的乙腈分子不同）。此外，在水-有机混合物的酶活性位点中检测到的有机溶剂分子与在相应纯有机溶剂中的结构中的位置相同。
