Poster Presentation The 48th Lorne Conference on Protein Structure and Function 2023

INVESTIGATING THE INTERACTIONS OF FRAGMENT ANALOGUES AGAINST A BACTERIAL RECEPTOR AND ITS HUMAN HOMOLOG FOR ANTIBIOTIC LEADS (#318)

Madeline S McRae 1 , Lorna Wilkinson-White 2 , Brendon Wang 1 , Rezwan Siddiquee 1 , Biswarajan Mohanty 2 , Anthony P Duff 3 , Sandro F Ataide 1 , Ann H Kwan 1 4
  1. School of Life and Environmental Sciences, University of Sydney, Sydney, NSW, Australia
  2. Sydney Analytical Core Facility, University of Sydney, Sydney, NSW, Australia
  3. National Deuteration Facility, ANSTO, Lucas Heights, NSW, Australia
  4. Sydney Nano Institute, University of Sydney, Sydney, NSW, Australia

The rapid global emergence of antibiotic resistance in the past number of decades necessitates the development of new antibiotics with a novel mechanism. FtsY, a receptor protein for prokaryotic signal recognition particle (SRP) was deemed as a potential antibiotic target due to its essential role in protein folding and proper targeting of nascent polypeptides to their sub-cellular destination. SRP and its receptor (SR) are functionally conserved across all living organisms, but the FtsY NG-domain in prokaryotes are uniquely engaged in a protein:RNA interaction with its SRP partner while its eukaryotic homolog, SRα-NG, binds other SRP proteins which then mediate interactions with RNA. Targeting the unique FtsY-NG:RNA interaction will open up opportunities for novel antibiotic development.

Fragment Based Drug Design (FBDD) is an effective tool used in drug development where weakly bound fragments are evolved into potent drug-like molecules. Through FBDD, we have developed fragment analogues that bind to the FtsY-NG RNA-interaction site with moderate affinities [1]. Further structure-activity relationship (SAR) studies between FtsY-NG and the compounds will be presented. Several compounds were initially found to bind our target site. Next, counter-screening of these compounds against SRα-NG were performed following optimisation of folded SRα-NG production with improved purity and stability. The counter-screening study has identified and eliminated compounds that possessed undesirable interactions while favouring those that bind FtsY-NG specifically. Additionally, an in-house whole-cell screening protocol was established to observe the antimicrobial activities of the compounds. These results yielded important SARs needed to improve the specificity and affinity of the compounds for FtsY-NG with the plan to further develop them into antibiotic leads.

 

  1. Faoro, C., Wilkinson-White, L., Kwan, A. H., and Ataide, S. F. (2018) Discovery of fragments that target key interactions in the signal recognition particle (SRP) as potential leads for a new class of antibiotics. PloS one 13, e0200387