An atypical interaction explains the high-affinity of a non-hydrolyzable S-linked 1,6-alpha-mannanase inhibitor.
Belz, T., Jin, Y., Coines, J., Rovira, C., Davies, G.J., Williams, S.J.(2017) Chem Commun (Camb) 53: 9238-9241
- PubMed: 28766587 
- DOI: https://doi.org/10.1039/c7cc04977c
- Primary Citation of Related Structures:  
5M77, 5N0F - PubMed Abstract: 
The non-hydrolyzable S-linked azasugars, 1,6-α-mannosylthio- and 1,6-α-mannobiosylthioisofagomine, were synthesized and shown to bind with high affinity to a family 76 endo-1,6-α-mannanase from Bacillus circulans. X-ray crystallography showed an atypical interaction of the isofagomine nitrogen with the catalytic acid/base. Molecular dynamics simulations reveal that the atypical binding results from sulfur perturbing the most stable form away from the nucleophile interaction preferred for the O-linked congener.
Organizational Affiliation: 
School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia. sjwill@unimelb.edu.au.