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    • Keywords


      Green fluorescent protein; proton transfer; pH-jump; caged proton; protein dynamics

    • Abstract


      The sub-millisecond protonation dynamics of the chromophore in S65T mutant form of the green fluorescent protein (GFP) was tracked after a rapid pH jump following laser-induced proton release from the caged photolabile compoundo-nitrobenzaldehyde. Following a jump in pH from 8 to 5 (which is achieved within 2 μs), the fluorescence of S65T GFP decreased as a single exponential with a time constant of ∼90 μs. This decay is interpreted as the conversion of the deprotonated fluorescent GFP chromophore to a protonated non-fluorescent species. The protonation kinetics showed dependence on the bulk viscosity of the solvent, and therefore implicates bulk solvent-controlled protein dynamics in the protonation process. The protonation is proposed to be a sequential process involving two steps: (a) proton transfer from solvent to the chromophore, and (b) internal structural rearrangements to stabilize a protonated chromophore. The possible implications of these observations to protein dynamics in general is discussed

    • Author Affiliations


      Roop Mallik1 2 Jayant B Udgaonkar1 G Krishnamoorthy3

      1. National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bangalore - 560 065, India
      2. Department of Developmental & Cell Biology, University of California Irvine, 2302 Natural Sciences 1, Irvine, CA - 92697, USA
      3. Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai - 400 005, India
    • Dates

  • Journal of Chemical Sciences | News

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