报告时间：2024年11月30日 上午10:00 (10:00, Nov.30, 2024)

报告地点：物质楼A309会议室(RoomA309 , Material Science Building)

报告题目：Site-Specific Labeling Reveals Cas9 Induces Partial Unwinding Without RNA/DNA Pairing in Sequences Distal to the PAM

报告人：李越，明济生物制药（北京）有限公司首席科学家

报告摘要：

CRISPR-Cas9 is an RNA-guided nuclease that has been widely adapted for genome engineering. A key determinant in Cas9 target selection is DNA duplex unwinding to form an R-loop, in which the single-stranded RNA guide hybridizes with one of the DNA strands. To advance understanding on DNA unwinding by Cas9, we combined two types of spectroscopic label, 2-aminopurine and nitroxide spin-label-EPR, to investigate unwinding at a specific DNA base pair induced by Streptococcus pyogenes Cas9. Data obtained with RNA guide lengths varying from 13 to 20 nucleotide revealed that the DNA segment distal to the protospacer adjacent motif can adopt a “partial unwinding” state, in which a mixture of DNA-paired and DNA-unwound populations exist in equilibrium. Significant unwinding can occur at positions not supported by RNA/DNA pairing, and the degree of unwinding depends on RNA guide length and modulates DNA cleavage activity. The results shed light on Cas9 target selection and may inform developments of genome-engineering strategies.

报告人简介：

李越，明济生物制药（北京）有限公司首席科学家，于北达科他州立大学获生物化学博士学位，博士期间主要研究方向为细胞自噬调控蛋白调控的结构机理。之后在南加州大学进行博士后研究，师从Dr. Peter Z. Qin，博士后主要研究方向是通过EPR及荧光方法研究CRISPR对DNA的解旋机理。2022年5月回国后加入明济生物从事抗肿瘤及针对自身免疫疾病的抗体药物的研发工作。曾获南加州大学Arthur W. Adamson 杰出博士后奖，回国后入选北京市第十八批海外高层次引进人才，北京市大兴区“新国门“优秀青年。