title: A structural biology approach enables the development of antimicrobials targeting bacterial immunophilins.
abstract: Macrophage infectivity potentiators (Mips) are immunophilin proteins and essential virulence factors for a range of pathogenic organisms. We applied a structural biology approach to characterize a Mip from Burkholderia pseudomallei (BpML1), the causative agent of melioidosis. Crystal structure and nuclear magnetic resonance analyses of BpML1 in complex with known macrocyclics and other derivatives led to the identification of a key chemical scaffold. This scaffold possesses inhibitory potency for BpML1 without the immunosuppressive components of related macrocyclic agents. Biophysical characterization of a compound series with this scaffold allowed binding site specificity in solution and potency determinations for rank ordering the set. The best compounds in this series possessed a low-micromolar affinity for BpML1, bound at the site of enzymatic activity, and inhibited a panel of homologous Mip proteins from other pathogenic bacteria, without demonstrating toxicity in human macrophages. Importantly, the in vitro activity of BpML1 was reduced by these compounds, leading to decreased macrophage infectivity and intracellular growth of Burkholderia pseudomallei. These compounds offer the potential for activity against a new class of antimicrobial targets and present the utility of a structure-based approach for novel antimicrobial drug discovery.
authors.affiliation: Emerald Bio, Bainbridge Island, Washington, USA.
authors.forename: Darren W
authors.initials: DW
authors.lastname: Begley
authors.forename: David
authors.initials: D
authors.lastname: Fox
authors.forename: Dominic
authors.initials: D
authors.lastname: Jenner
authors.forename: Christina
authors.initials: C
authors.lastname: Juli
authors.forename: Phillip G
authors.initials: PG
authors.lastname: Pierce
authors.forename: Jan
authors.initials: J
authors.lastname: Abendroth
authors.forename: Muigai
authors.initials: M
authors.lastname: Muruthi
authors.forename: Kris
authors.initials: K
authors.lastname: Safford
authors.forename: Vanessa
authors.initials: V
authors.lastname: Anderson
authors.forename: Kateri
authors.initials: K
authors.lastname: Atkins
authors.forename: Steve R
authors.initials: SR
authors.lastname: Barnes
authors.forename: Spencer O
authors.initials: SO
authors.lastname: Moen
authors.forename: Amy C
authors.initials: AC
authors.lastname: Raymond
authors.forename: Robin
authors.initials: R
authors.lastname: Stacy
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Myler
authors.forename: Bart L
authors.initials: BL
authors.lastname: Staker
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Harmer
authors.forename: Isobel H
authors.initials: IH
authors.lastname: Norville
authors.forename: Ulrike
authors.initials: U
authors.lastname: Holzgrabe
authors.forename: Mitali
authors.initials: M
authors.lastname: Sarkar-Tyson
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Edwards
authors.forename: Donald D
authors.initials: DD
authors.lastname: Lorimer
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001426:Bacterial Proteins / Q000187:drug effects* / Q000648:ultrastructure; D001665:Binding Sites; D016957:Burkholderia pseudomallei / Q000187:drug effects*; D018360:Crystallography, X-Ray; D055808:Drug Discovery / Q000379:methods*; D020104:Immunophilins / Q000187:drug effects* / Q000648:ultrastructure; D019906:Nuclear Magnetic Resonance, Biomolecular; D037521:Virulence Factors
chemical_list: D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D037521:Virulence Factors; D020104:Immunophilins; C000592660:ML1 protein, Burkholderia pseudomallei