Advanced Resistance Studies Identify Two Discrete Mechanisms in <i>Staphylococcus aureus</i> to Overcome Antibacterial Compounds that Target Biotin Protein Ligase
Andrew J. Hayes,
Jiulia Satiaputra,
Louise M. Sternicki,
Ashleigh S. Paparella,
Zikai Feng,
Kwang J. Lee,
Beatriz Blanco-Rodriguez,
William Tieu,
Bart A. Eijkelkamp,
Keith E. Shearwin,
Tara L. Pukala,
Andrew D. Abell,
Grant W. Booker,
Steven W. Polyak
Affiliations
Andrew J. Hayes
School of Biological Sciences, University of Adelaide, South Australia 5005, Australia
Jiulia Satiaputra
School of Biological Sciences, University of Adelaide, South Australia 5005, Australia
Louise M. Sternicki
School of Biological Sciences, University of Adelaide, South Australia 5005, Australia
Ashleigh S. Paparella
School of Biological Sciences, University of Adelaide, South Australia 5005, Australia
Zikai Feng
School of Biological Sciences, University of Adelaide, South Australia 5005, Australia
Kwang J. Lee
School of Physical Sciences, University of Adelaide, South Australia 5005, Australia
Beatriz Blanco-Rodriguez
School of Physical Sciences, University of Adelaide, South Australia 5005, Australia
William Tieu
School of Physical Sciences, University of Adelaide, South Australia 5005, Australia
Bart A. Eijkelkamp
School of Biological Sciences, University of Adelaide, South Australia 5005, Australia
Keith E. Shearwin
School of Biological Sciences, University of Adelaide, South Australia 5005, Australia
Tara L. Pukala
School of Physical Sciences, University of Adelaide, South Australia 5005, Australia
Andrew D. Abell
School of Physical Sciences, University of Adelaide, South Australia 5005, Australia
Grant W. Booker
School of Biological Sciences, University of Adelaide, South Australia 5005, Australia
Steven W. Polyak
School of Biological Sciences, University of Adelaide, South Australia 5005, Australia
Biotin protein ligase (BPL) inhibitors are a novel class of antibacterial that target clinically important methicillin-resistant Staphylococcus aureus (S. aureus). In S. aureus, BPL is a bifunctional protein responsible for enzymatic biotinylation of two biotin-dependent enzymes, as well as serving as a transcriptional repressor that controls biotin synthesis and import. In this report, we investigate the mechanisms of action and resistance for a potent anti-BPL, an antibacterial compound, biotinyl-acylsulfamide adenosine (BASA). We show that BASA acts by both inhibiting the enzymatic activity of BPL in vitro, as well as functioning as a transcription co-repressor. A low spontaneous resistance rate was measured for the compound (−9) and whole-genome sequencing of strains evolved during serial passaging in the presence of BASA identified two discrete resistance mechanisms. In the first, deletion of the biotin-dependent enzyme pyruvate carboxylase is proposed to prioritize the utilization of bioavailable biotin for the essential enzyme acetyl-CoA carboxylase. In the second, a D200E missense mutation in BPL reduced DNA binding in vitro and transcriptional repression in vivo. We propose that this second resistance mechanism promotes bioavailability of biotin by derepressing its synthesis and import, such that free biotin may outcompete the inhibitor for binding BPL. This study provides new insights into the molecular mechanisms governing antibacterial activity and resistance of BPL inhibitors in S. aureus.