Native β- barrel substrates pass through two shared intermediates during folding on the BAM complex

• 成果类型: Article
• 署名作者: dos Santos, Thiago M. A.; Thomson, Benjamin D.; Marquez, Melissa D.; Pan, Lydia; Monfared, Tabasom H.; Kahne, Daniel E.
• 署名单位: Northeastern University; Harvard University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-15342
• DOI: 10.1073/pnas.2409672121
• 发表日期: 2024-10-15
• 关键词: outer-membrane; escherichia-coli; yaet complex; lipopolysaccharide; identification; biogenesis; proteins; gene

摘要

The assembly of beta- barrel proteins into membranes is mediated by the evolutionarily numerous substrates which vary considerably in size and shape. How BAM is able to efficiently fold such a diverse array of beta- barrel substrates is not clear. Here, we develop a disulfide crosslinking method to trap native substrates in vivo as they fold on BAM. By placing a cysteine within the luminal wall of the BamA barrel as well as in the substrate beta- strands, we can compare the residence time of each substrate strand within the We used this method to characterize stable intermediates which occur during folding of two structurally different native substrates. Strikingly, these intermediates occur during identical stages of folding for both substrates: soon after folding has begun and just before folding is completed. We suggest that these intermediates arise due to barriers to folding that are common between beta- barrel substrates, and that the BAM catalyst is able to fold so many different substrates because it addresses these common challenges.