Title:Ubiquitous Existence of Cation-Proton Antiporter and its Structurefunction
Interplay: A Clinical Prospect
Volume: 24
Issue: 1
Author(s): Manish Dwivedi*Sowdhamini Mahendiran
Affiliation:
- Amity Institute of Biotechnology, Amity University Uttar Pradesh, Lucknow-226028, India
Keywords:
Cation-proton antiporters, structure, transporter, Ec-NhaA, ion exchange, membrane proteins.
Abstract: Sodium, potassium, and protons are the most important ions for life on earth, and their homeostasis
is crucially needed for the survival of cells. The biological cells have developed a system
that regulates and maintains the integrity of the cells by facilitating the exchange of these ions. These
systems include the specific type of ion transporter membrane proteins such as cation-proton antiporters.
Cation proton antiporters induce the active transport of cations like Na+, K+ or Ca+ across the
cell membrane in exchange for protons (H+) and make the organism able to survive in alkaline conditions,
high or fluctuating pH, stressed temperature or osmolarity. The secondary transporter proteins
exploit the properties of various specific structural components to carry out efficient active transport.
Ec-NhaA crystal structure was resolved at acidic pH at which the protein is downregulated, which discloses
the presence of 12 transmembrane (TM) helices. This structural fold, the “NhaA fold,” is speculated
to contribute to the cation-binding site and conformational alterations during transport in various
antiporters. Irrespective of the variation in the composition of amino acids and lengths of proteins, several
other members of the CPA family, such as NmABST, PaNhaP, and MjNhaP1, share the common
structural features of the Ec-NhaA. The present review elucidates the existence of CPAs throughout all
the kingdoms and the structural intercorrelation with their function. The interplay in the structurefunction
of membrane transporter protein may be implemented to explore the plethora of biological
events such as conformation, folding, ion binding and translocation etc.