Title:An Overview of the Selectivity and Efficiency of the Bacterial Carbonic Anhydrase Inhibitors
VOLUME: 22 ISSUE: 18
Author(s):C. Capasso and C.T. Supuran
Affiliation:Istituto di Bioscienze e Biorisorse, CNR, via Pietro Castellino 111-80131 Napoli, Italy.
Keywords:Anions, antibacterial, antiinfective, carbonic anhydrase, CA inhibitors, hydratase activity, pathogens, selective inhibition,
sulfonamide, X-ray.
Abstract:The possibility to develop new antibacterial agents raised much interest recently. The main classes of antibiotics
clinically used nowadays act towards the inhibition of four classical targets: a) cell wall biosynthesis; b) protein biosynthesis;
c) DNA and RNA biosynthesis; d) folate biosynthesis. Recently, carbonic anhydrases (CAs, EC 4.2.1.1) started
to be investigated in detail in pathogenic bacteria, in the search for antibiotics with a novel mechanism of action, since it
has been demonstrated that in many bacteria, CAs are essential for the life cycle of the organism and that their inhibition
leads to growth impairment or growth defects of the pathogen. CAs catalyze a simple but physiologically relevant reaction
in all life kingdoms, carbon dioxide hydration to bicarbonate and protons. Several classes of CA inhibitors (CAIs) are
known to date: the metal complexing anions and the unsubstituted sulfonamides, which bind to the Zn(II) ion of the enzyme
either by substituting the non-protein zinc ligand or add to the metal coordination sphere, generating trigonal–
bipyramidal species are the classical, most frequently investigated ones. In many cases effective inhibitors were detected,
some of which also inhibited the bacterial growth in vivo. However, very few of the detected inhibitors were also selective
for the bacterial over the human, off target isoforms such as hCA II. Using structure-based drug design processes, we estimate
that it will be possible to achieve the desired selectivity for inhibiting preferentially the bacterial but not the host
CA isoforms.
