Proton binding sites and conformational analysis of H+K(+)-ATPase.
It is proposed that the hydronium ion, H3O+, binds to the E1 conformation of the alpha-subunit of gastric proton pump. The H3O+ binding cavities are characterized parametrically based on valence, sequence, geometry, and size considerations from comparative modeling. The cavities have scope for accommodating monovalent cations of different ionic radii. The H3O+ transport is proposed to be aided by arenes which are arranged regularly along the pump starting from N-domain through the transmembrane region. Step-by-step structural changes accompanying H3O+ occlusion are studied in detail. The observations corroborate well with earlier experimental studies.
Chourasia
Mukesh
M
Molecular Modelling Group, Organic Chemical Sciences, Indian Institute of Chemical Technology, Hyderabad 500007, India.
Sastry
G Madhavi
GM
Sastry
G Narahari
GN
D000255:Adenosine Triphosphate / Q000378:metabolism; D001665:Binding Sites; D002414:Cations, Monovalent / Q000737:chemistry; D017506:H(+)-K(+)-Exchanging ATPase / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D009861:Onium Compounds / Q000737:chemistry*; D011487:Protein Conformation; D011522:Protons
D002414:Cations, Monovalent; D009861:Onium Compounds; D011522:Protons; C027727:hydronium ion; D000255:Adenosine Triphosphate; D017506:H(+)-K(+)-Exchanging ATPase