Fragment-guided design of subnanomolar beta-lactamase inhibitors active in vivo.
Eidam, O., Romagnoli, C., Dalmasso, G., Barelier, S., Caselli, E., Bonnet, R., Shoichet, B.K., Prati, F.(2012) Proc Natl Acad Sci U S A 109: 17448-17453
- PubMed: 23043117 
- DOI: https://doi.org/10.1073/pnas.1208337109
- Primary Citation of Related Structures:  
4E3I, 4E3J, 4E3K, 4E3L, 4E3M, 4E3N, 4E3O - PubMed Abstract: 
Fragment-based design was used to guide derivatization of a lead series of β-lactamase inhibitors that had heretofore resisted optimization for in vivo activity. X-ray structures of fragments overlaid with the lead suggested new, unanticipated functionality and points of attachment. Synthesis of three derivatives improved affinity over 20-fold and improved efficacy in cell culture. Crystal structures were consistent with the fragment-based design, enabling further optimization to a K(i) of 50 pM, a 500-fold improvement that required the synthesis of only six derivatives. One of these, compound 5, was tested in mice. Whereas cefotaxime alone failed to cure mice infected with β-lactamase-expressing Escherichia coli, 65% were cleared of infection when treated with a cefotaxime:5 combination. Fragment complexes offer a path around design hurdles, even for advanced molecules; the series described here may provide leads to overcome β-lactamase-based resistance, a key clinical challenge.
Organizational Affiliation: 
Department of Pharmaceutical Chemistry, University of California, 1700 Fourth Street, Byers Hall, San Francisco, CA 94158, USA.