Dynamic mechanisms of neutral amino acid exchanger ASCT2 transporting substrate glutamine

This study focuses on the molecular mechanism by which the neutral amino acid transporter protein ASCT2 mediates glutamine (Gln) transport and its dual role in cancer and metabolism. The dynamic gating mechanism of the helical hairpin structure HP2 in ASCT2 was revealed by microsecond classical molecular dynamics (CMD) and Gaussian accelerated molecular dynamics (GaMD) simulations combined with Markov state modelling (MSM). It was found that the C467R mutation destabilises the HP2 conformation and impairs the efficiency of Gln binding and transport, while the prolonged opening time of HP2 in the substrate-bound state suggests that dietary Gln may affect the transport function by stabilising the conformation.MSM analyses further identified the transition of HP2 from ‘closed’ to ‘open’. MSM analysis further identified the key pathway of HP2 from ‘closed’ to ‘open’ (S2→S15→S10→S6→S5→S7→S19, 16.76% probability). These results not only provide a theoretical basis for the development of ASCT2-targeted anticancer drugs, but also open up new ideas for the design of functional foods based on the regulation of amino acid metabolism by natural compounds.