TY - JOUR
T1 - How ligands modulate the gastric H,K-ATPase activity and its inhibition by tegoprazan
AU - Cerf, N.T.
AU - Zerbetto de Palma, G.
AU - Fedosova, Natalya
AU - Filomatori, C. V.
AU - Rossi, Rolando C.
AU - Faraj, S.E.
AU - Montes, Monica
N1 - Publisher Copyright:
© 2024 The Authors
PY - 2024/12
Y1 - 2024/12
N2 - The introduction of potassium-competitive acid blockers (P-CABs) has been a major innovation in gastric H,K-ATPase inhibition and many laboratories are actively engaged in the development of novel molecules within this class. This work investigates the interaction between H,K-ATPase and tegoprazan, a representative of the P-CABs group, in terms of K+ and H+ binding, through functional and structural analyses. First, by studying the H,K-ATPase activity, we found a model to describe the non-Michaelis-Menten kinetics through a “ping-pong” mechanism that explains a stoichiometry of 1 H+, 1 K+, and 1 ATP molecule, but also considering the influence of H+ on the ionization states of the protein. A kinetic evaluation of the inhibition of tegoprazan denotes the binding to two different intermediates states with apparent Kd (μM) 0.56 ± 0.04 and 2.70 ± 0.24 at pH 7.2. Molecular dynamics simulations revealed important changes in the interactions of tegoprazan with the transmembrane residues depending on whether the site contains K+ or not. This explains the decrease in affinity as a function of K+ concentration observed in the kinetic experiments. On the other hand, the structures predict that the protonation of tegoprazan is responsible for the change in its dihedral angle. The rotation of the benzimidazole ring allows the inhibitor to be positioned further into the luminal cavity, a situation compatible with the higher inhibition affinity of H,K-ATPase measured at low pH. Results presented herein will provide a basis for the rational design of novel P-CABs ligands.
AB - The introduction of potassium-competitive acid blockers (P-CABs) has been a major innovation in gastric H,K-ATPase inhibition and many laboratories are actively engaged in the development of novel molecules within this class. This work investigates the interaction between H,K-ATPase and tegoprazan, a representative of the P-CABs group, in terms of K+ and H+ binding, through functional and structural analyses. First, by studying the H,K-ATPase activity, we found a model to describe the non-Michaelis-Menten kinetics through a “ping-pong” mechanism that explains a stoichiometry of 1 H+, 1 K+, and 1 ATP molecule, but also considering the influence of H+ on the ionization states of the protein. A kinetic evaluation of the inhibition of tegoprazan denotes the binding to two different intermediates states with apparent Kd (μM) 0.56 ± 0.04 and 2.70 ± 0.24 at pH 7.2. Molecular dynamics simulations revealed important changes in the interactions of tegoprazan with the transmembrane residues depending on whether the site contains K+ or not. This explains the decrease in affinity as a function of K+ concentration observed in the kinetic experiments. On the other hand, the structures predict that the protonation of tegoprazan is responsible for the change in its dihedral angle. The rotation of the benzimidazole ring allows the inhibitor to be positioned further into the luminal cavity, a situation compatible with the higher inhibition affinity of H,K-ATPase measured at low pH. Results presented herein will provide a basis for the rational design of novel P-CABs ligands.
KW - gastric acidity treatment
KW - H,K-ATPase
KW - inhibition mechanism
KW - kinetic models
KW - P-CABs
KW - P-type ATPase
KW - tegoprazan
UR - http://www.scopus.com/inward/record.url?scp=85211375920&partnerID=8YFLogxK
U2 - 10.1016/j.jbc.2024.107986
DO - 10.1016/j.jbc.2024.107986
M3 - Journal article
C2 - 39547508
AN - SCOPUS:85211375920
SN - 0021-9258
VL - 300
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 12
M1 - 107986
ER -