Design and testing of selective inactivators against an antifungal enzyme target

Development of Efficient Covalent Inactivators of a Fungal Aspartate Semialdehyde Dehydrogenase

Aspartate semialdehyde dehydrogenase (ASADH) catalyzes the second step in the fungal pathway towards the synthesis of threonine, isoleucine, and methionine, and it has been identified as a viable target for antifungal drug development. Our previous work produced a group of vinyl sulfones that function as irreversible covalent inactivators of this enzyme. We have now expanded this initial set to produce vinyl sulfones with higher kinetic efficiency as covalent inactivators of ASADH purified from the pathogenic fungal species Candida albicans. The catalytic efficiency of these inactivators has also been compared to related classes of irreversible inactivators, vinyl sulfonamides, acrylamides, and sulfonyl ketones.

Synthesis of aromatic glycoconjugates as anti-fungal agents against Candida spp. and assessment of their covalent crosslinking capabilities

Covalent drugs are becoming increasingly attractive in drug discovery, as they can enhance potency and selectivity for their molecular targets. Covalent inhibitors have been investigated for several therapeutic applications, including anti-cancer and anti-infection agents. However, there are only a few examples of covalent inhibitors targeting fungal pathogens. We have previously reported aromatic glycoconjugates (AGCs) capable of inhibiting the adhesion of Candida albicans to buccal epithelial cells. In this work, we synthesize novel derivatives of the AGCs to which we have added reactive functional groups, such as acryloyl and vinyl sulfones, and investigated their antifungal efficacy against Candida spp. Although the compounds were ineffective at clinically relevant concentrations, we found that some of the galactose derivatives featuring reactive groups were amongst the most active, so their ability to crosslink nucleophilic side chains was assessed in model reactions.

Structural-functional analysis of drug target aspartate semialdehyde dehydrogenase

Aspartate β-semialdehyde dehydrogenase (ASADH) is a key enzyme in the biosynthesis of essential amino acids in microorganisms and some plants. Inhibition of ASADHs can be a potential drug target for developing novel antimicrobial and herbicidal compounds. This review covers up-to-date information about sequence diversity, ligand/inhibitor-bound 3D structures, potential inhibitors, and key pharmacophoric features of ASADH useful in designing novel and target-specific inhibitors of ASADH. Most reported ASADH inhibitors have two highly electronegative functional groups that interact with two key arginyl residues present in the active site of ASADHs. The structural information, active site binding modes, and key interactions between the enzyme and inhibitors serve as the basis for designing new and potent inhibitors against the ASADH family.