Bushra Zubair1, Danish Idrees2, Faizan Ahmad2, Md. Imtaiyaz Hassan2
1NICT, Sikkim Manipal university, India.
2Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India.
Carbonic anhydrase (CA) is a Zn +2 -containing enzyme that catalyzes the reversible hydration of carbon dioxide: CO 2 + H 2 O ↔ HCO ~3− + H +. There are five evolutionarily unrelated CA families, designated as α, β, γ, δ and ε. All human CAs are related to α family. Total 15 types of human CAs are studied so far including, CAI, CAII, CAIII, CAIV, CAV, CAVI, CAVII, CAVIII, CAIX, CAX, CAXI, CAXII, CAXIII, CAXIV, and CAV. They differ widely in their cellular localization like structure and function. Except three isozymes (CAVIII, CAX and CAXI), all CAs shows catalytic activity. Some CAs are marker of tumor hypoxia and a prognostic factor in several human cancers, involved in solid tumor acidification, osteopetrosis, breast cancer etc. We have performed an extensive analysis of CAs for its structure and function in order to establish a structure-function relationship. All of them have the same tertiary fold, with a central 10-stranded β-sheet as the dominating secondary structure element. The Zn+2 ion is located in a cone-shaped cavity and coordinated to three histidine residues and a solvent molecule. Inhibitors usually bind at or near the metal ion centre by a hydrogen-bonded system. Our structure-function analysis will provide an insight of structure-function relationship. Read More …