Chromophore deprotonation state alters the optical properties of blue chromoprotein

Cheng Yi Chiang, Cheng Chung Lee, Shin Yi Lo, Andrew H.J. Wang, Huai Jen Tsai

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Chromoproteins (CPs) have unique colors and can be used in biological applications. In this work, a novel blue CP with a maximum absorption peak (λmax) at 608 nm was identified from the carpet anemone Stichodactyla gigantea (sgBP). In vivo expression of sgBP in zebrafish would change the appearance of the fishes to have a blue color, indicating the potential biomarker function. To enhance the color properties, the crystal structure of sgBP at 2.25 Å resolution was determined to allow structure-based protein engineering. Among the mutations conducted in the Gln-Tyr-Gly chromophore and chromophore environment, a S157C mutation shifted the λmax to 604 nm with an extinction coefficient (ε) of 58,029 M-1-cm-1 and darkened the blue color expression. The S157C mutation in the sgBP chromophore environment could affect the color expression by altering the deprotonation state of the phenolic group in the chromophore. Our results provide a structural basis for the blue color enhancement of the biomarker development.

Original languageEnglish
Article numbere0134108
JournalPLoS ONE
Issue number7
Publication statusPublished - Jul 28 2015
Externally publishedYes

ASJC Scopus subject areas

  • General Biochemistry,Genetics and Molecular Biology
  • General Agricultural and Biological Sciences
  • General


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