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Publication Abstract from PubMed

Insulins in the venom of certain fish-hunting cone snails facilitate prey capture by rapidly inducing hypoglycemic shock. One such insulin, Conus geographus G1 (Con-Ins G1), is the smallest known insulin found in nature and lacks the C-terminal segment of the B chain that, in human insulin, mediates engagement of the insulin receptor and assembly of the hormone's hexameric storage form. Removal of this segment (residues B23-B30) in human insulin results in substantial loss of receptor affinity. Here, we found that Con-Ins G1 is monomeric, strongly binds the human insulin receptor and activates receptor signaling. Con-Ins G1 thus is a naturally occurring B-chain-minimized mimetic of human insulin. Our crystal structure of Con-Ins G1 reveals a tertiary structure highly similar to that of human insulin and indicates how Con-Ins G1's lack of an equivalent to the key receptor-engaging residue PheB24 is mitigated. These findings may facilitate efforts to design ultrarapid-acting therapeutic insulins.

A minimized human insulin-receptor-binding motif revealed in a Conus geographus venom insulin.,Menting JG, Gajewiak J, MacRaild CA, Chou DH, Disotuar MM, Smith NA, Miller C, Erchegyi J, Rivier JE, Olivera BM, Forbes BE, Smith BJ, Norton RS, Safavi-Hemami H, Lawrence MC Nat Struct Mol Biol. 2016 Sep 12. doi: 10.1038/nsmb.3292. PMID:27617429^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.