12月10日，哈佛医学院细胞生物学系博士后李颜颜来访，进行学术交流。
报告题目：Structural mechanism of lipopolysaccharide remodeling and transportation

摘要： Lipopolysaccharide (LPS) in Gram-negative bacteria is essential for cell envelope formation and resistance to antibiotics. The LPS transport (Lpt) proteins (LptA-G) move LPS from the inner to outer membrane. With associated LptC, LptB2FG in the inner membrane functions as an ATP-binding cassette (ABC) transporter to extract LPS out of the membrane. The mechanism of the entire LptB2FGC complex and the role of LptC in LPS extraction are poorly understood. Here, we have used single-particle cryo-EM to characterize LptB2FGC and LptB2FG in nucleotide-free and nucleotide-bound states. A series of cryo-EM structures reveal the basis of stepwise LPS capture, elevation and extrusion, all coupled with distinct conformational rearrangement of LptB2FGC. LptC inserts its transmembrane helix between the two transmembrane domains of LptB2FG, representing an unprecedented regulatory mechanism for ABC transporters. Our structural and functional analyses present a detailed molecular movie of the tightly regulated and highly efficient process of LptB2FGC-driven LPS extraction.

报告人介绍：哈佛医学院细胞生物学系博士后，先后在美国杜克大学，美国马里兰大学学习访问研究。主要研究方向为病原微生物LPS(内毒素)的结构与功能，LPS分子调控及其致病机制，LPS转运蛋白的转运机制。先后两次获得国际内毒素协会“青年学者“荣誉称号，在微生物领域重要刊物PNAS, Nature等发表多篇研究论文。