Vinogradov Alexander A, Evans Ethan D, Pentelute Bradley L
Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , MA 02139 , USA . Email:
Chem Sci. 2015 May 1;6(5):2997-3002. doi: 10.1039/c4sc03877k. Epub 2015 Mar 23.
In this study we synthesized and characterized mirror image barnase ( ribonuclease). d-Barnase was identical to l-barnase, when analyzed by liquid chromatography and mass-spectrometry. Proteolysis of the mirror image enzyme revealed that in contrast to its native counterpart, d-barnase was completely stable to digestive proteases. In enzymatic assays, d-barnase had the reciprocal chiral specificity and was fully active towards mirror image substrates. Interestingly, d-barnase also hydrolyzed the substrate of the native chirality, albeit 4000 times less efficiently. This effect was further confirmed by digesting a native 112-mer RNA with the enzyme. Additional studies revealed that barnase accommodates a range of substrates with various chiralities, but the prime requirement for guanosine remains. These studies point toward using mirror image enzymes as modern agents in biotechnology.
在本研究中，我们合成并表征了镜像核糖核酸酶（barnase）。通过液相色谱和质谱分析，发现d-核糖核酸酶与l-核糖核酸酶相同。对镜像酶进行蛋白水解后发现，与天然对应物不同，d-核糖核酸酶对消化蛋白酶完全稳定。在酶促测定中，d-核糖核酸酶具有相反的手性特异性，对镜像底物具有完全活性。有趣的是，d-核糖核酸酶也能水解天然手性的底物，尽管效率要低4000倍。用该酶消化天然的112聚体RNA进一步证实了这一效应。额外的研究表明，核糖核酸酶能容纳一系列具有不同手性的底物，但对鸟苷的主要需求仍然存在。这些研究表明，镜像酶可作为生物技术中的现代试剂。
