PhD Scientific Days 2021

PH_I_P: Pharmaceutical Sciences I. Posters

Insights into the substrate binding mechanism of SULT1A1 through Molecular Dynamics with excited Normal Modes simulations

Text of the abstract

Sulfotransferases (SULTs) are a diverse family of phase II metabolizing enzymes. They catalyse sulfate transfer from its co-factor, 3′-Phosphoadenosine 5′-Phosphosulfate (PAPS) to a large variety of substrates. Even though the tertiary structure of the family is very similar, the substrates vary considerably in size and function, and the enzyme is utilized in different organs, for different purposes in the human body. The aim of our project is to better understand the conformational space of this diverse family of enzymes, starting from SULT1A1. It has been previously suggested that a considerable shift of SULT structure caused by PAPS binding could control the capability of SULT to bind large substrates. We employed molecular dynamics (MD) simulations and the recently developed approach of MD with excited Normal Modes (MDeNM) to elucidate molecular mechanisms guiding the recognition of diverse substrates and inhibitors by SULT1A1. MDeNM allowed exploring an extended conformational space of PAPS-bound SULT1A1, which has not been achieved up to now by using classical MD. The generated ensembles combined with docking of 132 SULT1A1 ligands shed new light on substrate and inhibitor binding mechanisms. Unexpectedly, our simulations and analyses on binding of the substrates estradiol and fulvestrant demonstrated that large conformational changes of the PAPS-bound SULT1A1 could occur independently on the co-factor movements that could be sufficient to accommodate large substrates as fulvestrant. Such structural displacements detected by the MDeNM simulations in the presence of the co-factor suggest that a wider range of drugs could be recognized by PAPS-bound SULT1A1 and highlight the utility of including MDeNM in protein-ligand interactions studies where major rearrangements are expected. This poster is based on the article by the same authors, accepted for publication in Scientific Reports. This project has been funded by the French ANR (project ToxME), Paris Univ., Inserm Institute, French-Hungarian bilateral program NKFIH 2019-2.1.11-TÉT-2020-00096, Thematic Excellence Programme (2020-4.1.1.-TKP2020) of the Ministry for Innovation and Technology in Hungary.

University and Doctoral School

Semmelweis University, Doctoral School of Pharmaceutical Sciences