Structural Characterization of Acylimine-Containing Blue and Red Chromophores in mTagBFP and TagRFP Fluorescent Proteins

Oksana M. Subach, Vladimir N. Malashkevich, Wendy D. Zencheck, Kateryna S. Morozova, Kiryl D. Piatkevich, Steven C. Almo, Vladislav V. Verkhusha

Research output: Contribution to journalArticle

70 Scopus citations

Abstract

We determined the 2.2 Å crystal structures of the red fluorescent protein TagRFP and its derivative, the blue fluorescent protein mTagBFP. The crystallographic analysis is consistent with a model in which TagRFP has the trans coplanar anionic chromophore with the conjugated π-electron system, similar to that of DsRed-like chromophores. Refined conformation of mTagBFP suggests the presence of an N-acylimine functionality in its chromophore and single Cα-Cβ bond in the Tyr64 side chain. Mass spectrum of mTagBFP chromophore-bearing peptide indicates a loss of 20 Da upon maturation, whereas tandem mass spectrometry reveals that the Cα-N bond in Leu63 is oxidized. These data indicate that mTagBFP has a new type of the chromophore, N-[(5-hydroxy-1H-imidazole-2-yl)methylidene]acetamide. We propose a chemical mechanism in which the DsRed-like chromophore is formed via the mTagBFP-like blue intermediate.

Original languageEnglish (US)
Pages (from-to)333-341
Number of pages9
JournalChemistry and Biology
Volume17
Issue number4
DOIs
StatePublished - Apr 23 2010

Keywords

  • CHEMBIO

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Medicine
  • Molecular Biology
  • Pharmacology
  • Drug Discovery
  • Clinical Biochemistry

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