Structure-based Drug Design of SPSB2-iNOS Inhibitors: Identification of Potential Lead Compounds via <em>In Silico</em> Screening, NMR and SPR Experiments — ASN Events
  1. Schedule
  2. Session Five - Poster Session A
  3. Structure-based Drug Design of SPSB2-iNOS Inhibitors: Identification of Potential Lead Compounds via In Silico Screening, NMR and SPR Experiments

Structure-based Drug Design of SPSB2-iNOS Inhibitors: Identification of Potential Lead Compounds via In Silico Screening, NMR and SPR Experiments (#168)

Beow Keat Yap 1 , Eleanor W.W. Leung 1 , Irene R. Chassagnon 1 , Jitendra R. Harjani 1 , Mark D. Mulcair 1 , David K. Chalmers 1 , Jamie S. Simpson 1 , Martin J. Scanlon 1 , Raymond S. Norton 1
  1. Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia

The SPRY domain-containing SOCS box protein 2 (SPSB2) interacts with inducible nitric oxide synthase (iNOS), a critical effector of the innate host response that is required for the intracellular killing of pathogens such as Mycobacterium tuberculosis and Leishmania major. The SPSB2-iNOS interaction results in proteosomal degradation of iNOS. Consistent with this, SPSB2-deficient macrophages have significantly elevated levels of both iNOS and nitric oxide (NO). This suggests that inhibitors of SPSB2-iNOS interactions may prolong the lifetime of iNOS and therefore NO production, and thereby enhance the killing of persistent pathogens.1,2  

In this study, in silico screening was undertaken to identify potential hits with binding modes which match that of the DINNN sequence of iNOS at the SPSB2-iNOS binding interface.3 These compounds were further analysed with surface Plasmon resonance (SPR) and nuclear magnetic resonance (NMR) experiments, in particular saturation transfer difference spectroscopy (STD) and Carr-Purcell- Meiboom-Gill (CPMG) relaxation experiments, to confirm the binding interactions and estimate affinities. Potential lead compounds were identified and optimization of these compounds is currently in progress to yield compounds with higher binding affinities.

  1. Kuang, Z. et al. The SPRY domain-containing SOCS box protein SPSB2 targets iNOS for proteasomal degradation. J Cell Biol 190, 129-141 (2010).
  2. Lewis, R. S. et al. TLR regulation of SPSB1 controls inducible nitric oxide synthase induction. J Immunol 187, 3798-3805 (2011).
  3. Filippakopoulos, P. et al. Structural basis for Par-4 recognition by the SPRY domain- and SOCS box-containing proteins SPSB1, SPSB2, and SPSB4. J Mol Biol 401, 389-402 (2010).