Alteration of citrine structure by hydrostatic pressure explains the accompanying spectral shift

Buz Barstow, Nozomi Ando, Chae Un Kim, Sol M. Gruner

Research output: Contribution to journalArticlepeer-review

65 Scopus citations


A protein molecule is an intricate system whose function is highly sensitive to small external perturbations. However, no examples that correlate protein function with progressive subangstrom structural perturbations have thus far been presented. To elucidate this relationship, we have investigated a fluorescent protein, citrine, as a model system under high-pressure perturbation. The protein has been compressed to produce deformations of its chromophore by applying a high-pressure cryocooling technique. A closely spaced series of x-ray crystallographic structures reveals that the chromophore undergoes a progressive deformation of up to 0.8 Å at an applied pressure of 500 MPa. It is experimentally demonstrated that the structural motion is directly correlated with the progressive fluorescence shift of citrine from yellow to green under these conditions. This protein is therefore highly sensitive to subangstrom deformations and its function must be understood at the subangstrom level. These results have significant implications for protein function prediction and biomolecule design and engineering, because they suggest methods to tune protein function by modification of the protein scaffold.

Original languageEnglish (US)
Pages (from-to)13362-13366
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number36
StatePublished - Sep 9 2008

All Science Journal Classification (ASJC) codes

  • General


  • Fluorescence
  • High-pressure x-ray crystallography
  • Protein engineering
  • Protein structure-function
  • Yellow fluorescent protein


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