Modification of aniline containing proteins using an oxidative coupling strategy

Area of Science:

• Chemical Biology
• Organic Chemistry
• Biochemistry

Background:

• Protein modification is crucial for biochemical research and therapeutic development.
• Existing bioconjugation methods often lack specificity or require harsh conditions.
• Developing novel, chemoselective reactions for protein labeling remains an active area of research.

Purpose of the Study:

• To develop a new chemoselective bioconjugation reaction for modifying proteins.
• To establish a method for the specific labeling of proteins with aniline derivatives.
• To create stable and versatile protein-bioconjugates for various applications.

Main Methods:

• Developed an oxidative coupling reaction for aniline modification.
• Utilized lysine acylation and native chemical ligation to attach aryl amines to proteins.
• Confirmed product identity using ESI-MS and small molecule analogs.
• Assessed bioconjugate stability across a range of pH and chemical conditions.

Main Results:

• Achieved rapid oxidative coupling of anilines to N,N-dialkyl-N'-acyl-p-phenylenediamines on protein surfaces.
• Demonstrated that native amino acids do not participate in the reaction.
• Confirmed high stability of the resulting bioconjugates (pH 4-11, various reagents).
• Synthesized a fluorescent reagent for detecting aniline-labeled proteins and successfully PEGylated green fluorescent protein.

Conclusions:

• The developed bioconjugation reaction offers a highly specific and stable method for protein labeling.
• This technique is compatible with existing protein engineering strategies, including unnatural amino acid incorporation.
• The method holds significant potential for diverse applications requiring precise control over protein modification and detection.