Session: Parallel session 9 - Complex mixtures - polymers - microplastics

First characterisation of the Mycobacterium tuberculosis orphan CYP135B1 identified as a new target of the antituberculosis drug SQ109

Elodie SADOWSKI¹, Nicolas PIETRANCOSTA^1,3, Jean-Luc BOUCHER⁴, Cédric PIONNEAU⁵, Olivier POCH⁶, Claudine MEYER^6,7, Alexandra AUBRY^2,8, Emmanuelle SACHON¹

¹Sorbonne Université, Laboratoire des Biomolécules, Paris, France
²Centre d'Immunologie et des Maladies Infectieuses, Cimi-Paris, INSERM U1135, Sorbonne Université, Paris, France
³Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), INSERM U1130, CNRS UMR8246, Sorbonne Université, Paris, France
⁴Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, CNRS UMR 8601, Université Paris Cité, Paris, France
⁵Plateforme Post-génomique de la Pitié Salpêtrière (P3S), UMS 37 PASS, Sorbonne Université, , Paris, France
⁶ICube-CSTB, UMR 7357, Centre de Recherche en Biomédecine de Strasbourg, Strasbourg, France
⁷Université Paris Cité, Paris, France
⁸Centre National de Référence des Mycobactéries et de la Résistance des Mycobactéries aux Antituberculeux, Laboratoire de Bactériologie-Hygiène, Assistance Publique-Hôpitaux de Paris (APHP), Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Paris, France

The emergence of the multidrug-resistant tuberculosis strains has generated a need for new effective antituberculosis (anti-TB) drugs and the characterisation of novel drug targets. As such, Mycobacterium tuberculosis (Mtb) P450s are considered as promising novel therapeutic targets. Therefore, we combined bioinformatic and modeling studies, biochemistry, UV-visible and EPR spectroscopy, and mass spectrometry to successfully express, purify and characterise the most prevalent Mtb P450, the orphan CYP135B1. Purified CYP135B1 displays typical spectroscopic features for members of this hemoprotein superfamily with tight binding of several imidazole derivatives with its FeIII-heme. Very interestingly, CYP135B1 metabolises the new promising anti-TB drug SQ109 on its geranyl moiety with insertion of an O-atom at positions distinct from that observed in the case of Mtb CYP124A1. Docking studies using our CYP135B1 3D-homology model suggest that these differences might be due to a different binding mode of SQ109 at the active site compared to that observed in the CYP124-SQ109 co-crystal structure (PDB code: 6T0J). These results are of great importance to decipher the SQ109 mechanism of action and understand the role of Mtb P450s.