Download MendeleyCH•••S hydrogen bonds drive molecular recognition of ergothioneine by the microbial transporter.
Legg, K.A., Gonzalez-Gutierrez, G., Edmonds, K.A., Shushkov, P.G., Giedroc, D.P.(2026) Sci Adv 12: eaeb0426-eaeb0426
- PubMed: 41719410
- DOI: https://doi.org/10.1126/sciadv.aeb0426
- Primary Citation Related Structures:
9EGH, 9EGI, 9EGJ, 9O5F - PubMed Abstract:
Many bacteria harbor an ATP-binding cassette (ABC) transporter named EgtU specific for the human dietary antioxidant and 2-thioimidazole-containing low-molecular weight thiol ergothioneine (ET). How the solute binding domain, EgtUC, discriminates among ET and other similar molecules is unknown. Here, we use a "chimeric" mutagenesis strategy and two distantly related EgtUCs from Streptococcus pneumoniae and Helicobacter pylori to show that a suite of EgtUC alkyl CH•••S hydrogen bonds to the ET thione S atom are central determinants of molecular recognition. Small perturbations in CH•••S distance and angle give rise to sharply attenuated transport-competent ET-bound "closed" state lifetimes and increased motional disorder in the binding pocket, not around the S atom itself, but distally in weakening NH•••O hydrogen bonds. This work highlights the impact of alkyl CH•••S H bonding in a biological protein-ligand complex in water.
- Department of Chemistry, Indiana University, Bloomington, IN, USA.
Organizational Affiliation:
