The γ-class carbonic anhydrase EcoCAγ, reported in Escherichia coli in 2022, contains a 72-residue N-terminal extension absent in the canonical YrdA isoform. A genomic analysis confirmed that the full-length EcoCAγ is conserved (95-100% identity) across multiple E. coli and Shigella strains but is not present in the laboratory strain K-12. A full-length trimeric model was generated using AlphaFold-Multimer and subjected to molecular dynamics simulations in aqueous and membrane environments. In membrane conditions, the N-terminal segment maintained an extended α-helical conformation, whereas in aqueous solution it underwent compaction and self-association. Throughout all simulations, the trimeric assembly and the geometry of the catalytic site remained preserved. No disruption of the active-site architecture was observed under either condition. These simulations provide structurally resolved observations of the environment-dependent behavior of the N-terminal region and its effect on the conformational dynamics of the EcoCAγ trimer.
16 March 2026 in Acta Crystallographica Section F Structural Biology Communications