Local Conformational Constraint of Firefly Luciferase Can Affect the Energy of Bioluminescence and Enzyme Stability

Chao Zhang, Xiaoguang Bai, Shengxi Chen, Larisa M. Dedkova, Sidney M. Hecht

Research output: Contribution to journalArticlepeer-review


Conformational dynamics contribute importantly to enzyme catalysis, such that targeted conformational constraint may affect catalysis. Firefly luciferases undergo extensive structural change during catalysis; key residues form a hydrophobic pocket, excluding water and enabling maximally energetic light production. Point mutants almost always luminesce at longer wavelengths (lower energy) than the wild type. Conformational constraint, using dipeptide analogue 3 at a position critical for optimized excited state structure, produced luciferase emission at a shorter wavelength by ∼10 nm. Incomparison, introduction of conformationally constrained analogues 4, 5, or 7 afforded luciferases emitting at longer wavelengths, while a related unconstrained luciferase (analogue 6) exhibited wild-type emission. The constrained luciferases tested were more stable than the wild type. Protein modeling demonstrated that the "inside" or "outside" orientation of the conformationally constrained dipeptide led to the shorter or longer emission wavelength, respectively. More broadly, these results suggest that local conformational constraint can control specific elements of enzyme behavior, both in vitro and in vivo. This represents the first example of studying enzyme function by introducing conformationally constrained dipeptides at a specific protein position. The principles discovered here in luciferase modification will enable studies to control the wavelength emission and photophysical properties of modified luciferases.

Original languageEnglish (US)
Pages (from-to)1695-1707
Number of pages13
JournalCCS Chemistry
Issue number5
StatePublished - May 2022


  • conformational constraint
  • genetic code reprogramming
  • luciferase bioluminescence and stability
  • modified ribosomes
  • protein modeling

ASJC Scopus subject areas

  • Chemistry(all)


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