The insertion of bioactive peptides at the C-terminal end of an 11S globulin changes the structural stability and improves the antihypertensive activity
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Keywords

Amaranth
Antihypertensive peptides
Bioactive
Culture media design
Globulin
Mature seeds
Potato waste
Protein engineering
Protein expression
Protein stability
Storage protein
Thermal stability

How to Cite

1.
Espinosa-Hernández E, Morales-Camacho JI, Fernández-Velasco DA, Benítez-Cardoza CG, Rosas-Cárdenas F de F, Luna-Suárez S. The insertion of bioactive peptides at the C-terminal end of an 11S globulin changes the structural stability and improves the antihypertensive activity. Electron. J. Biotechnol. [Internet]. 2019 Jan. 10 [cited 2024 Nov. 7];37. Available from: https://www.ejbiotechnology.info/index.php/ejbiotechnology/article/view/2018.11.001

Abstract

Background: The 11S globulin from amaranth is the most abundant storage protein in mature seeds and is well recognized for its nutritional value. We used this globulin to engineer a new protein by adding a four valinetyrosine antihypertensive peptide at its C-terminal end to improve its functionality. The new protein was named AMR5 and expressed in the Escherichia coli BL21-CodonPlus(DE3)-RIL strain using a custom medium (F8PW) designed for this work.

Results: The alternative medium allowed for the production of 652 mg/L expressed protein at the flask level, mostly in an insoluble form, and this protein was subjected to in vitro refolding. The spectrometric analysis suggests that the protein adopts a β/α structure with a small increment of α-helix conformation relative to the native amaranth 11S globulin. Thermal and urea denaturation experiments determined apparent Tm and C1/2 values of 50.4°C and 3.04 M, respectively, thus indicating that the antihypertensive peptide insertion destabilized the modified protein relative to the native one. AMR5 hydrolyzed by trypsin and chymotrypsin showed 14- and 1.3-fold stronger inhibitory activity against angiotensin I-converting enzyme (IC50 of 0.034 mg/mL) than the unmodified protein and the previously reported amaranth acidic subunit modified with antihypertensive peptides, respectively.

Conclusion: The inserted peptide decreases the structural stability of amaranth 11S globulin and improves its antihypertensive activity.

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