Investigating the interaction between organic anion transporter 1 and ochratoxin A: An in silico structural study to depict early molecular events of substrate recruitment and the impact of single point mutations.

Organic anion transporters (OATs) belong to a subgroup of the solute carrier 22 transporter family. OATs have a central role in xenobiotic disposition affecting the toxicokinetics of its substrates and inter-individual differences in their expression, activity and function impact both toxicokinetics and toxicodynamics. Amongst OATs, OAT1 (solute carrier family 22 member 6) is involved in the urinary excretion of many xenobiotics bringing substrates into renal proximal tubular cells which can then be secreted across the apical membrane into the tubule lumen. The mycotoxin ochratoxin A has been shown to have a high affinity for OAT1, which is an important renal transporter involved in its urinary excretion. Nowadays, molecular modeling techniques are widely applied to assess protein-ligand interactions and may provide a tool to depict the mechanic of xenobiotic action be it toxicokinetics or toxicodynamics. This work provides a structured pipeline consisting of docking and molecular dynamic simulations to study OAT1-ligand interactions and the impact of OAT1 polymorphisms on such interactions. Such a computational structure-based analytical framework allowed to: i) model OAT1-substrate complex formation and depict the features correlating its sequence, structure and its capability to recruit substrates; and ii) investigate the impact of OAT1 missense mutations on substrate recruitment. Perspectives on applying such a structured pipeline to xenobiotic-metabolising enzymes are discussed.