Journal: Nat Chem Biol / Year: 2022 Title: Symmetric and asymmetric receptor conformation continuum induced by a new insulin. Authors: Xiaochun Xiong / Alan Blakely / Jin Hwan Kim / John G Menting / Ingmar B Schäfer / Heidi L Schubert / Rahul Agrawal / Theresia Gutmann / Carlie Delaine / Yi Wolf Zhang / Gizem Olay Artik / ...Authors: Xiaochun Xiong / Alan Blakely / Jin Hwan Kim / John G Menting / Ingmar B Schäfer / Heidi L Schubert / Rahul Agrawal / Theresia Gutmann / Carlie Delaine / Yi Wolf Zhang / Gizem Olay Artik / Allanah Merriman / Debbie Eckert / Michael C Lawrence / Ünal Coskun / Simon J Fisher / Briony E Forbes / Helena Safavi-Hemami / Christopher P Hill / Danny Hung-Chieh Chou / Abstract: Cone snail venoms contain a wide variety of bioactive peptides, including insulin-like molecules with distinct structural features, binding modes and biochemical properties. Here, we report an active ...Cone snail venoms contain a wide variety of bioactive peptides, including insulin-like molecules with distinct structural features, binding modes and biochemical properties. Here, we report an active humanized cone snail venom insulin with an elongated A chain and a truncated B chain, and use cryo-electron microscopy (cryo-EM) and protein engineering to elucidate its interactions with the human insulin receptor (IR) ectodomain. We reveal how an extended A chain can compensate for deletion of B-chain residues, which are essential for activity of human insulin but also compromise therapeutic utility by delaying dissolution from the site of subcutaneous injection. This finding suggests approaches to developing improved therapeutic insulins. Curiously, the receptor displays a continuum of conformations from the symmetric state to a highly asymmetric low-abundance structure that displays coordination of a single humanized venom insulin using elements from both of the previously characterized site 1 and site 2 interactions.
EMPIAR-10736 (Title: Cryo-EM of the human insulin receptor ectodomain in complex with an insulin analog with truncated B chain and enlongated A chain Data size: 11.7 TB Data #1: Unaligned multi-frame micrographs (40 e-/A2 dose) [micrographs - multiframe] Data #2: unaligned micrographs (60 e-/A2 dose) [micrographs - multiframe])
A: Insulin A chain B: Insulin B chain E: Isoform Short of Insulin receptor C: Insulin A chain D: Insulin B chain G: Insulin A chain H: Insulin B chain I: Insulin A chain J: Insulin B chain F: Isoform Short of Insulin receptor hetero molecules