Global Replacement of Tryptophan with Aminotryptophans Generates Non-Invasive Protein-Based Optical pH Sensors

Abstract

Functional protein design: Replacement of the tryptophan indole moiety in proteins with aminoindoles converts pH-insensitive into pH-sensitive fluorescent proteins (see picture). Such global substitution of residues in target proteins by noncanonical amino acids with defined spectral properties offers a unique approach for the design of protein-based molecular sensors.