Engineered bacterial host for genetic encoding of physiologically stable protein nitration

Area of Science:

• Biochemistry
• Molecular Biology
• Biotechnology

Background:

• Protein function relies on synergistic amino acid interactions and post-translational modifications (PTMs).
• Protein nitration, a PTM linked to diseases, is challenging to maintain due to physiological reduction.
• Genetic code expansion allows encoding and precise installation of PTMs, including nitration.

Purpose of the Study:

• To develop a bacterial host for stable production of proteins with nitro groups.
• To overcome the physiological reduction of nitro groups during protein synthesis.
• To demonstrate the utility of this host for producing modified biomolecules.

Main Methods:

• Engineered an *Escherichia coli* host by removing six nitroreductase-associated genes.
• Utilized the engineered strain for producing proteins and peptides with incorporated nitro groups.
• Applied the host to synthesize biomolecules with photocaged amino acids, like ortho-nitrobenzyl-tyrosine.

Main Results:

• Successfully created a bacterial strain that stably produces proteins containing nitro groups.
• Demonstrated enhanced production of biomolecules with nitro groups, crucial for photocleavability.
• Showcased the incorporation of photocaged non-canonical amino acids (ncAAs) into Elastin-Like Polypeptides.

Conclusions:

• The engineered *E. coli* host is an effective tool for producing nitro-containing proteins and peptides.
• This technology facilitates the creation of custom biomolecules for research and biotechnology.
• Enables advancements in areas requiring precise control over protein chemical properties and photocleavability.