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Updated: Jan 27, 2026

The Use of a β-lactamase-based Conductimetric Biosensor Assay to Detect Biomolecular Interactions
Published on: February 1, 2018
Equilibrium partially folded states of B. licheniformis -lactamase
Valeria A Risso1,2, Mario R Ermácora3,4
1Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes, Roque Sáenz Peña 352, B1876BXD, Bernal, Buenos Aires, Argentina.
Abstract:
-Lactamases (penicillinases) facilitate bacterial resistance to antibiotics and are excellent theoretical and experimental models in protein structure, dynamics and evolution. Bacillus licheniformis exo-small penicillinase (ESP) is a Class A -lactamase with three tryptophan residues located one in each of its two domains and one in the interface between domains. The conformational landscape of three well-characterized ESP TrpPhe mutants was characterized in equilibrium unfolding experiments by measuring tryptophan fluorescence, far-UV CD, activity, hydrodynamic radius, and limited proteolysis. The TrpPhe substitutions had little impact on the native conformation, but changed the properties of the partially folded states populated at equilibrium. The results were interpreted in the framework of modern theories of protein folding.
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