Rational Design of a Novel Fluorescent Biosensor for β-Lactam Antibiotics from a Class A β-Lactamase

Pak Ho Chan, Hong Bing Liu, Yu Wai Chen, Kwok Chu Chan, Chun Wai Tsang, Yun Chung Leung, Kwok Yin Wong

Research output: Journal article publicationJournal articleAcademic researchpeer-review

64 Citations (Scopus)


A rational design strategy was used to construct a sensitive "turn-on" biosensor for β-lactam antibiotics and β-lactamase inhibitors from a class A β-lactamase mutant with suppressed hydrolytic activity. A fluorescein molecule was attached to the 166 position on the Ω-loop of the E166C mutant close to the active site of the β-lactamase. Upon binding with antibiotics or inhibitors, the flexibility of the Ω-loop allows the fluorescein molecule to move out from the active site and be more exposed to solvent. This process is accompanied by an increase in the fluorescence of the labeled enzyme. The fluorescence intensity of the biosensor increases with the concentration of antibiotics or inhibitors, which can detect penicillin G at concentrations as low as 50 nM in water. This approach opens a possibility for converting highly active and nonallosteric enzymes into substrate-binding proteins for biosensing purposes.
Original languageEnglish
Pages (from-to)4074-4075
Number of pages2
JournalJournal of the American Chemical Society
Issue number13
Publication statusPublished - 7 Apr 2004

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry


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