gRAMP CRISPR-Cas是一种与caspase样肽酶结合的RNA内切酶，这一成果由荷兰代尔夫特理工大学Stan J. J. Brouns研究团队经过不懈努力而取得。该研究成果发表在2021年8月26日出版的国际学术期刊《科学》上。

研究人员介绍了一种来自韧皮部杆菌属“Scalindua brodae”内的III-E型效应子，称为 Sb-gRAMP，它由单个基因编码，具有融合在一起的几个III型结构域。该效应器使用CRISPR RNA来指导目标RNA识别，并在相距6个核苷酸的两个既定位置切割单链RNA。有趣的是，Sb-gRAMP与半胱天冬酶样TPR-CHAT肽酶结合形成Caspase（CRISPR引导的半胱天冬酶）复合物。该研究揭示了目标RNA激活蛋白酶活性从而产生病毒免疫的潜在机制。 

据悉，III型CRISPR-Cas免疫在原核生物中广泛存在，通常由多亚基效应复合物介导。这些复合物识别互补的病毒转录本并能激活辅助免疫蛋白。

附：英文原文

Title: The gRAMP CRISPR-Cas effector is an RNA endonuclease complexed with a caspase-like peptidase

Author: Sam P. B. van Beljouw, Anna C. Haagsma, Alicia Rodríguez-Molina, Daan F. van den Berg, Jochem N. A. Vink, Stan J. J. Brouns

Issue&Volume: 2021/08/26

Abstract: Type III CRISPR-Cas immunity is widespread in prokaryotes and is generally mediated by multi-subunit effector complexes. These complexes recognize complementary viral transcripts and can activate ancillary immune proteins. Here, we describe a type III-E effector from Candidatus “Scalindua brodae”, called Sb-gRAMP, which is natively encoded by a single gene with several type III domains fused together. This effector uses CRISPR RNA to guide target RNA recognition and cleaves single-stranded RNA at two defined positions six nucleotides apart. Intriguingly, the Sb-gRAMP physically combines with the caspase-like TPR-CHAT peptidase to form the Craspase (CRISPR-guided Caspase) complex, pointing at a potential mechanism of target RNA-induced protease activity to gain viral immunity.

DOI: 10.1126/science.abk2718

Source: https://science.sciencemag.org/content/early/2021/08/25/science.abk2718