5′-[N-(d-biotinoyl)sulfamoyl]amino-5′-deoxyadenosine (Bio-AMS, 1) possesses selective activity against Mycobacterium tuberculosis (Mtb) and arrests fatty acid and lipid biosynthesis through inhibition of the Mycobacterium tuberculosis biotin protein ligase (MtBPL). Mtb develops spontaneous resistance to 1 with a frequency of at least 1 × 10-7 by overexpression of Rv3406, a type II sulfatase that enzymatically inactivates 1. In an effort to circumvent this resistance mechanism, we describe herein strategic modification of the nucleoside at the 5′-position to prevent enzymatic inactivation. The new analogues retained subnanomolar potency to MtBPL (KD = 0.66-0.97 nM), and 5′R-C-methyl derivative 6 exhibited identical antimycobacterial activity toward: Mtb H37Rv, MtBPL overexpression, and an isogenic Rv3406 overexpression strain (minimum inhibitory concentration, MIC = 1.56 μM). Moreover, 6 was not metabolized by recombinant Rv3406 and resistant mutants to 6 could not be isolated (frequency of resistance <1.4 × 10-10) demonstrating it successfully overcame Rv3406-mediated resistance.
Bibliographical noteFunding Information:
This work was supported by a grant (AI091790 to D.S.) from the National Institutes of Health as well as the University of Minnesota Bighley Fellowship. Isothermal titration calorimetry was carried out using an ITC-200 microcalorimeter, funded by the NIH Shared Instrumentation Grant S10-OD017982. Mass spectrometry was carried out in the Center for Mass Spectrometry and Proteomics, University of Minnesota. We also gratefully acknowledge Bruce Witthuhn for his contributions and assistance using the LC-MS/MS instruments. We also thank Carolyn Bertozzi for providing the Rv3406 over-expression plasmid. Finally, we acknowledge the Minnesota Supercomputing Institute (MSI) at the University of Minnesota for providing resources that contributed to the research results reported within this paper (http://www.msi.umn.edu).
- Mycobacterium tuberculosis
- biotin protein ligase
- bisubstrate inhibitor