claMP Tag: a versatile inline metal-binding platform based on the metal abstraction peptide

Area of Science:

• Bioconjugation
• Molecular Imaging
• Protein Engineering

Background:

• Molecularly targeted tools are crucial for disease research and diagnostics.
• Metals provide essential functionality, but protein conjugation is complex, especially for transition metals.
• Current methods yield heterogeneous mixtures and require extensive purification.

Purpose of the Study:

• To develop an alternative to chemical conjugation for metal-protein binding.
• To create a peptide tag for direct, inline metal incorporation into recombinant proteins.
• To assess the feasibility of using the metal abstraction peptide (MAP) sequence for transition metal binding.

Main Methods:

• Genetically engineering the MAP sequence into recombinant epidermal growth factor (EGF).
• Evaluating the impact of the claMP Tag on protein expression and folding.
• Assessing transition metal (nickel) incorporation into the tagged protein.

Main Results:

• The claMP Tag was successfully generated by incorporating the MAP sequence into EGF.
• The tag did not significantly impede protein expression, disulfide bond formation, or tertiary structure.
• The claMP Tag facilitated the incorporation of nickel, demonstrating linker-less metal conjugation.

Conclusions:

• The MAP sequence can be genetically incorporated into proteins as a functional tag (claMP Tag).
• This approach offers a simplified and more efficient method for creating metal-protein conjugates.
• The claMP Tag holds promise for expanding metal-based diagnostic and research tools.