Proton binding sites and conformational analysis of H+K(+)-ATPase

Mukesh Chourasia; G Madhavi Sastry; G Narahari Sastry

doi:10.1016/j.bbrc.2005.08.205

Proton binding sites and conformational analysis of H+K(+)-ATPase

Biochem Biophys Res Commun. 2005 Oct 28;336(3):961-6. doi: 10.1016/j.bbrc.2005.08.205.

Authors

Mukesh Chourasia¹, G Madhavi Sastry, G Narahari Sastry

Affiliation

¹ Molecular Modelling Group, Organic Chemical Sciences, Indian Institute of Chemical Technology, Hyderabad 500007, India.

PMID: 16157306
DOI: 10.1016/j.bbrc.2005.08.205

Abstract

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.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adenosine Triphosphate / metabolism
Binding Sites
Cations, Monovalent / chemistry
H(+)-K(+)-Exchanging ATPase / chemistry*
H(+)-K(+)-Exchanging ATPase / metabolism
Humans
Models, Molecular*
Onium Compounds / chemistry*
Protein Conformation
Protons*

Substances

Cations, Monovalent
Onium Compounds
Protons
hydronium ion
Adenosine Triphosphate
H(+)-K(+)-Exchanging ATPase