6JR3

Crystal structure of insulin hexamer fitted into cryo EM density map where each dimer was kept as rigid body

Summary for 6JR3

• Entry DOI: 10.2210/pdb6jr3/pdb
• EMDB information: 9878
• Descriptor: Insulin A chain, Insulin B chain (2 entities in total)
• Functional Keywords: insulin fibrillation, natural polyphenols, anti-amyloid activity, insulin hexamer, bioavailability, hormone
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 12
• Total formula weight: 34905.91

Authors

Sengupta, J.,Pathak, B.K.,Bhakta, S. (deposition date: 2019-04-02, release date: 2020-04-22, Last modification date: 2024-03-27)

Primary citation

Pathak, B.K.,Das, D.,Bhakta, S.,Chakrabarti, P.,Sengupta, J.
Resveratrol as a nontoxic excipient stabilizes insulin in a bioactive hexameric form.
J.Comput.Aided Mol.Des., 34:915-927, 2020

PubMed Abstract: Insulin aggregation is the leading cause of considerable reduction in the amount of active drug molecules in liquid formulations manufactured for diabetes management. Phenolic compounds, such as phenol and m-cresol, are routinely used to stabilize insulin in a hexameric form during its commercial preparation. However, long term usage of commercial insulin results in various adverse secondary responses, for which toxicity of the phenolic excipients is primarily responsible. In this study we aimed to find out a nontoxic insulin stabilizer. To that end, we have selected resveratrol, a natural polyphenol, as a prospective nontoxic insulin stabilizer because of its structural similarity with commercially used phenolic compounds. Atomic force microscopy visualization of resveratrol-treated human insulin revealed that resveratrol has a unique ability to arrest hINS in a soluble oligomeric form having discrete spherical morphology. Most importantly, resveratrol-treated insulin is nontoxic for HepG2 cells and it effectively maintains low blood glucose in a mouse model. Cryo-electron microscopy revealed 3D morphology of resveratrol-stabilized insulin that strikingly resembles crystal structures of insulin hexamer formulated with m-cresol. Significantly, we found that, in a condition inductive to amyloid fibrillation at physiological pH, resveratrol is capable of stabilizing insulin more efficiently than m-cresol. Thus, this study describes resveratrol as an effective nontoxic natural molecule that can be used for stabilizing insulin in a bioactive oligomeric form during its commercial formulation.

PubMed: 32270361
DOI: 10.1007/s10822-020-00311-3

Experimental method

ELECTRON MICROSCOPY (14.5 Å)