Development of Affimer Reagents to Modulate the Enzyme Activity of NDM-1

Antimicrobial resistance is leading to the reduction of effective antibiotics and is a global crisis. Metallo-β-lactamases (MBLs) hydrolyse and inactivate a diverse range of β-lactam antibiotics. New Delhi metallo-β-lactamase 1 (NDM-1) can confer resistance to all available β-lactam antibiotics and the rapid, global dissemination of the blaNDM-1 gene has raised concern. Co-administration of β-lactamase inhibitors with currently available β-lactam antibiotics is a proven strategy to re-sensitise drug resistant bacteria. However, an effective and specific NDM-1 inhibitor remains elusive. Therefore, the development of highly specific Affimer reagents that inhibit NDM-1 activity may provide an alternative approach for targeting this protein. Previous work has isolated Affimer 21 as an effective inhibitor of NDM-1 mediated hydrolysis of β-lactams. Affinity maturation of the Affimer 21 isolated a second candidate Affimer, CTL-18, as an effective inhibitor of NDM-1 activity. The isolation of CTL-18 by phage display informed potential changes to the methods to isolate even more effective binders. By increasing the stringency of the phage display strategy resulted in the isolation of a third candidate Affimer, CTL-C8. Further characterisation of binding and investigations into the use of Affimers as an effective NDM-1 inhibitor is required. However, the isolated Affimers presented could provide a stepping stone in the fight against antimicrobial resistance.