Aggregation-driven expression of liraglutide precursors using engineered mini-tags in Escherichia coli

An engineered 4.0 kDa fusion tag called LP8 let E. coli produce the liraglutide precursor mostly as insoluble inclusion bodies, giving an actual recovered yield of 14.6 mg/L after purification. Among 11 tested tags, LP8 balanced small tag mass with efficient inclusion-body formation and gave the highest expression.

Journal article — In vitro recombinant expression comparison. Population: Escherichia coli expressing liraglutide precursor. Sample size: 11 fusion tag constructs. Interventions: Recombinant expression of liraglutide precursor (Arg34-GLP-1(7-37)) with 11 cleavable fusion tags (LP1-LP11).

Among the 11 constructs, LP8 with a 4.0 kDa tag gave the highest fusion protein expression at 133 mg/L. Its calculated liraglutide precursor yield was 60 mg/L based on mass fraction (45% of fusion mass), and >95% of the fusion protein was insoluble, indicating efficient inclusion-body formation. After RP-HPLC purification, the actual recovered yield was 14.6 mg/L. LC/MS confirmed the purified peptide's identity and sequence integrity.

This paper matters for liraglutide research because it describes a compact fusion tag that gives high-yield, insoluble expression of the liraglutide precursor in E. coli, addressing the usual trade-off between tag size and peptide mass fraction. It does not establish whether the purified precursor is biologically active, whether the process scales, or whether the approach works for other GLP-1 analogs.

Key findings

• 11 cleavable fusion tag constructs (LP1-LP11) were engineered for Arg34-GLP-1(7-37) expression in E. coli.
• LP8, with a compact 4.0 kDa tag, achieved the highest expression: 133 mg/L of fusion protein.
• The calculated liraglutide precursor yield for LP8 was 60 mg/L, equal to 45% of the fusion mass.
• Actual recovered yield after RP-HPLC purification was 14.6 mg/L.
• LP8 produced efficient inclusion body formation, with >95% insolubility.
• Purified peptide identity and sequence integrity were confirmed by LC/MS.

Limitations

• Only one expression vector and host system were tested, so results may not generalise to other hosts or peptides.
• Actual recovered yield (14.6 mg/L) was much lower than the calculated yield (60 mg/L), indicating substantial purification losses.
• No large-scale fermentation or manufacturing performance was reported.
• The abstract reports no bioactivity or pharmacological testing of the purified liraglutide precursor.

The record

• Journal: Protein science : a publication of the Protein Society 35(6): e70594
• Published: 2026-05-18
• PMID: 42124529 — DOI: 10.1002/pro.70594
• MeSH terms: Escherichia coli, Recombinant Fusion Proteins, Protein Engineering, Glucagon-Like Peptide 1, Protein Aggregates, Liraglutide
• Author countries: India

Peptide profiles: Liraglutide.

All indexed evidence: Liraglutide trials & papers.

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