Heterologous expression and biochemical characterisation of the recombinant β-carbonic anhydrase (MpaCA) from the warm-blooded vertebrate pathogen malassezia pachydermatis

Abstract

Warm-blooded animals may have Malassezia pachydermatis on healthy skin, but changes in the skin microenvironment or host defences induce this opportunistic commensal to become pathogenic. Malassezia infections in humans and animals are commonly treated with azole antifungals. Fungistatic treatments, together with their long-term use, contribute to the selection and the establishment of drug-resistant fungi. To counteract this rising problem, researchers must find new antifungal drugs and enhance drug resistance management strategies. Cyclic adenosine monophosphate, adenylyl cyclase, and bicarbonate have been found to promote fungal virulence, adhesion, hydrolase synthesis, and host cell death. The CO₂/HCO₃^-/pH-sensing in fungi is triggered by HCO₃^- produced by metalloenzymes carbonic anhydrases (CAs, EC 4.2.1.1). It has been demonstrated that the growth of M. globosa can be inhibited in vivo by primary sulphonamides, which are the typical CA inhibitors. Here, we report the cloning, purification, and characterisation of the β-CA (MpaCA) from the pathogenic fungus M. pachydermatis, which is homologous to the enzyme encoded in the genome of M. globosa and M. restricta, that are responsible for dandruff and seborrhoeic dermatitis. Fungal CAs could be thus considered a new pharmacological target for combating fungal infections and drug resistance developed by most fungi to the already used drugs.

Keywords:

• Malassezia pachydermatis
• carbonic anhydrase
• CO₂-sensing
• bicarbonate
• protonography
• kinetic parameters
• sulphonamides

Acknowledgements

The authors are grateful to Valentina Brasiello and Giovanni Del Monaco for their technical assistance.

Disclosure statement

No potential conflict of interest was reported by the author(s). CT Supuran is Editor-in-Chief of the Journal of Enzyme Inhibition and Medicinal Chemistry, and he was not involved in the assessment, peer review, or decision-making process of this paper. The authors have no relevant affiliations of financial involvement with any organisation or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants, or patents received or pending, or royalties.

Additional information

Funding

This research was funded by the Italian Ministry of University and Research, project FISR2019_04819 BacCAD (to CC and CTS). Moreover, Fabrizio Carta (FC) is grateful to “Fondazione Cassa di Risparmio di Firenze [Grant Number ECR2018.1001] for supporting this work.