Random single amino acid deletion sampling unveils structural tolerance and the benefits of helical registry shift on GFP folding and structure.

ABSTRACT: Altering a protein's backbone through amino acid deletion is a common evolutionary mutational mechanism, but is generally ignored during protein engineering primarily because its effect on the folding-structure-function relationship is difficult to predict. Using directed evolution, enhanced green fluorescent protein (EGFP) was observed to tolerate residue deletion across the breadth of the protein, particularly within short and long loops, helical elements, and at the termini of strands. A variant with G4 removed from a helix (EGFP(G4Δ)) conferred significantly higher cellular fluorescence. Folding analysis revealed that EGFP(G4Δ) retained more structure upon unfolding and refolded with almost 100% efficiency but at the expense of thermodynamic stability. The EGFP(G4Δ) structure revealed

SUBMITTER: Arpino JA 

PROVIDER: S-EPMC4058518 | biostudies-literature | 2014 Jun

REPOSITORIES: biostudies-literature