Strijbis Karin, Ploegh Hidde L
Department of Infectious Diseases & Immunology, Utrecht University, Utrecht, The Netherlands.
Methods Mol Biol. 2014;1174:73-83. doi: 10.1007/978-1-4939-0944-5_5.
Circular proteins occur naturally and have been found in microorganisms, plants, and eukaryotes where they are commonly involved in host defense. Properties of circular proteins include enhanced resistance to exoproteases, increased thermostability, longer life spans, and increased activity. Using an enzymatic approach based on the bacterial sortase A (SrtA) transpeptidase, N- and C-termini of conventional linear proteins can be linked resulting in a circular protein. Circularization of bioengineered linear substrate proteins can indeed confer the desirable properties associated with circular proteins. Here, we describe how cells can be manipulated to secrete circularized proteins for substrates of choice via sortase-mediated circularization in the lumen of the endoplasmic reticulum.
环状蛋白天然存在，已在微生物、植物和真核生物中被发现，它们通常参与宿主防御。环状蛋白的特性包括对外切蛋白酶的抗性增强、热稳定性提高、寿命延长和活性增加。利用基于细菌分选酶A（SrtA）转肽酶的酶促方法，可以将传统线性蛋白的N端和C端连接起来，从而产生环状蛋白。生物工程线性底物蛋白的环化确实可以赋予与环状蛋白相关的理想特性。在这里，我们描述了如何通过内质网腔中的分选酶介导的环化来操纵细胞分泌针对所选底物的环化蛋白。
