Citations 1
Structural Basis for C 8 methylation of 23S ribosomal RNA by Cfr
Esakova, Olga , Jung, James , Lee, Hyunwook , Cho, Sung Hyun , Alumasa, John N., Schwalm, Erica L. , Bauerle, Matthew , Hafenstein, Susan , Yu, Zhiheng, Booker, Squire J. , Esakova, Olga A , Alumasa, John , Hafenstein, Susan L , Booker, Squire J , Grove, Tyler L. , Yu, Zhiheng
No container title available | March 3, 2026 | Volume: No volume available | Issue: No issue available | Pages: No page available
Abstract Cfr methylates C 8 of adenosine 2503 (A2503) in 23 S ribosomal RNA (rRNA) and will also methylate C 2 of A2503 after methylating C 8 . C 8 methylation confers resistance to more than five classes of clinically used antibiotics, highlighting it as a worrisome mechanism of antibiotic resistance. Here, we report the structure of Cfr, determined by cryogenic electron microscopy (Cryo-EM). Despite its small size (∼36 kDa), we exploit a transient protein–RNA crosslink that forms during catalysis, which requires Cys105 to resolve. Using a Cfr Cys105Ala variant and an 87-nucleotide strand of rRNA, we isolate the crosslinked species and determine its structure to 3.0 Å resolution. Notably, the 87-mer rRNA adopts an L-shaped conformation characteristic of tRNAs, rather than the conformation it assumes in the ribosome. One Sentence Summary Cryo-EM structure of Cfr, a radical S-adenosylmethionine methylase that confers antibiotic resistance