Structure-Based Optimization of Pyridoxal 5'-Phosphate-Dependent Transaminase Enzyme (BioA) Inhibitors that Target Biotin Biosynthesis in Mycobacterium tuberculosis

J Med Chem. 2017 Jul 13;60(13):5507-5520. doi: 10.1021/acs.jmedchem.7b00189. Epub 2017 Jun 22.

Abstract

The pyridoxal 5'-phosphate (PLP)-dependent transaminase BioA catalyzes the second step in the biosynthesis of biotin in Mycobacterium tuberculosis (Mtb) and is an essential enzyme for bacterial survival and persistence in vivo. A promising BioA inhibitor 6 containing an N-aryl, N'-benzoylpiperazine scaffold was previously identified by target-based whole-cell screening. Here, we explore the structure-activity relationships (SAR) through the design, synthesis, and biological evaluation of a systematic series of analogues of the original hit using a structure-based drug design strategy, which was enabled by cocrystallization of several analogues with BioA. To confirm target engagement and discern analogues with off-target activity, each compound was evaluated against wild-type (WT) Mtb in biotin-free and -containing medium as well as BioA under- and overexpressing Mtb strains. Conformationally constrained derivative 36 emerged as the most potent analogue with a KD of 76 nM against BioA and a minimum inhibitory concentration of 1.7 μM (0.6 μg/mL) against Mtb in biotin-free medium.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, N.I.H., Extramural

MeSH terms

  • Anti-Bacterial Agents / chemical synthesis
  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / pharmacology*
  • Bacterial Proteins / antagonists & inhibitors*
  • Bacterial Proteins / metabolism
  • Biocatalysis
  • Biotin / biosynthesis*
  • Dose-Response Relationship, Drug
  • Microbial Sensitivity Tests
  • Molecular Structure
  • Mycobacterium tuberculosis / drug effects*
  • Mycobacterium tuberculosis / metabolism
  • Piperazines / chemical synthesis
  • Piperazines / chemistry
  • Piperazines / pharmacology*
  • Pyridoxal Phosphate / metabolism*
  • Structure-Activity Relationship
  • Transaminases / antagonists & inhibitors*
  • Transaminases / metabolism

Substances

  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Piperazines
  • Pyridoxal Phosphate
  • Biotin
  • Transaminases
  • BioA protein, bacteria