Crystal Structure of the <b> <i>Aequorea victoria</i> </b> Green Fluorescent Protein

TLDR

The green fluorescent protein from the jellyfish *Aequorea victoria* is a widely used marker for gene expression, and its chromophore forms by spontaneous cyclization and oxidation of the Ser65‑Thr65‑Tyr66‑Gly67 sequence, requiring the native 11‑stranded β‑barrel fold for fluorescence. The crystal structure of Thr65 GFP was solved at 1.9 Å, and mutating the residue adjacent to the chromophore, Thr203, to tyrosine or histidine produced significantly red‑shifted excitation and emission maxima.

Abstract

The green fluorescent protein (GFP) from the Pacific Northwest jellyfish Aequorea victoria has generated intense interest as a marker for gene expression and localization of gene products. The chromophore, resulting from the spontaneous cyclization and oxidation of the sequence -Ser65 (or Thr65)-Tyr66-Gly67-, requires the native protein fold for both formation and fluorescence emission. The structure of Thr65 GFP has been determined at 1.9 angstrom resolution. The protein fold consists of an 11-stranded beta barrel with a coaxial helix, with the chromophore forming from the central helix. Directed mutagenesis of one residue adjacent to the chromophore, Thr203, to Tyr or His results in significantly red-shifted excitation and emission maxima.