State- dependent motion of a genetically encoded fluorescent biosensor

• 成果类型: Article
• 署名作者: Rosen, Paul C.; Horwitz, Samantha M.; Brooks, Daniel J.; Kim, Erica; Ambarian, Joseph A.; Waidmann, Lidia; Davis, Katherine M.; Yellen, Gary
• 署名单位: Harvard University; Harvard Medical School; Massachusetts Institute of Technology (MIT); Emory University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-13840
• DOI: 10.1073/pnas.2426324122
• 发表日期: 2025-03-11
• 关键词: gated k+ channel; mechanism; domain; sensor; DESIGN

摘要

Genetically encoded biosensors can measure biochemical properties such as small-molecule concentrations with single-cell resolution, even in vivo. Despite their utility, these sensors are black boxes: Very little is known about the structures of their low-and high-fluorescence states or what features are required to transition between them. We used LiLac, a lactate biosensor with a quantitative fluorescence-lifetime readout, as a model system to address these questions. X-ray crystal structures and engineered high-affinity metal bridges demonstrate that LiLac exhibits a large interdomain twist motion that pulls the fluorescent protein away from a sealed, high-lifetime state in the absence of lactate to a cracked, low-lifetime state in its presence. Understanding the structures and dynamics of LiLac will help to think about and engineer other fluorescent biosensors.