Structural insights and molecular dynamics into the inhibitory mechanism of a Kunitz-type trypsin inhibitor from Tamarindus indica L

J Enzyme Inhib Med Chem. 2021 Dec;36(1):480-490. doi: 10.1080/14756366.2021.1876686.

Abstract

Trypsin inhibitors from tamarind seed have been studied in vitro and in preclinical studies for the treatment of obesity, its complications and associated comorbidities. It is still necessary to fully understand the structure and behaviour of these molecules. We purifed this inhibitor, sequenced de novo by MALDI-TOF/TOF, performed its homology modelling, and assessed the interaction with the trypsin enzyme through molecular dynamics (MD) simulation under physiological conditions. We identified additional 75 amino acid residues, reaching approximately 72% of total coverage. The four best conformations of the best homology modelling were submitted to the MD. The conformation n°287 was selected considering the RMSD analysis and interaction energy (-301.0128 kcal.mol-1). Residues Ile (54), Pro (57), Arg (59), Arg (63), and Glu (78) of pTTI presented the highest interactions with trypsin, and arginine residues were mainly involved in its binding mechanism. The results favour bioprospecting of this protein for pharmaceutical health applications.

Keywords: Tamarind; antitryptic; computational methods; homology modelling; protein-protein interaction.

MeSH terms

  • Dose-Response Relationship, Drug
  • Molecular Dynamics Simulation*
  • Molecular Structure
  • Plant Extracts / chemistry
  • Plant Extracts / isolation & purification
  • Plant Extracts / pharmacology*
  • Seeds / chemistry
  • Structure-Activity Relationship
  • Tamarindus / chemistry*
  • Trypsin / metabolism*
  • Trypsin Inhibitors / chemistry
  • Trypsin Inhibitors / isolation & purification
  • Trypsin Inhibitors / pharmacology*

Substances

  • Plant Extracts
  • Trypsin Inhibitors
  • Trypsin

Grants and funding

This work was supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior [CAPES–Finance Code 001] and the Conselho Nacional de Desenvolvimento Cientítico e Tecnológico [CNPq–Award Number: 426116/2018–6].