Docking for fragment inhibitors of AmpC β-lactamase

Denise G. Teotico, Kerim Babaoglu, Gabriel Rocklin, Rafaela S. Ferreira, Anthony M. Giannetti, Brian K. Shoichet

Research output: Contribution to journalArticlepeer-review

82 Scopus citations

Abstract

Fragment screens for new ligands have had wide success, notwithstanding their constraint to libraries of 1,000-10,000 molecules. Larger libraries would be addressable were molecular docking reliable for fragment screens, but this has not been widely accepted. To investigate docking's ability to prioritize fragments, a library of > 137,000 such molecules were docked against the structure of β-lactamase. Forty-eight fragments highly ranked by docking were acquired and tested; 23 had K i values ranging from 0.7 to 9.2 mM. X-ray crystal structures of the enzyme-bound complexes were determined for 8 of the fragments. For 4, the correspondence between the predicted and experimental structures was high (RMSD between 1.2 and 1.4 Å), whereas for another 2, the fidelity was lower but retained most key interactions (RMSD 2.4-2.6 A). Two of the 8 fragments adopted very different poses in the active site owing to enzyme conformational changes. The 48% hit rate of the fragment docking compares very favorably with ''lead-like'' docking and high-throughput screening against the same enzyme. To understand this, we investigated the occurrence of the fragment scaffolds among larger, lead-like molecules. Approximately 1% of commercially available fragments contain these inhibitors whereas only 10 -7% of lead-like molecules do. This suggests that many more chemotypes and combinations of che- motypes are present among fragments than are available among lead-like molecules, contributing to the higher hit rates. The ability of docking to prioritize these fragments suggests that the technique can be used to exploit the better chemotype coverage that exists at the fragment level.

Original languageEnglish (US)
Pages (from-to)7455-7460
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume106
Issue number18
DOIs
StatePublished - May 5 2009

Keywords

  • Chemical space
  • Crystallography
  • Drug design
  • Hit rates

ASJC Scopus subject areas

  • General

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