5T7R

A6-A11 trans-dicarba human insulin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.55 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.194 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Insulin in motion: The A6-A11 disulfide bond allosterically modulates structural transitions required for insulin activity.

van Lierop, B.Ong, S.C.Belgi, A.Delaine, C.Andrikopoulos, S.Haworth, N.L.Menting, J.G.Lawrence, M.C.Robinson, A.J.Forbes, B.E.

(2017) Sci Rep 7: 17239-17239

  • DOI: 10.1038/s41598-017-16876-3

  • PubMed Abstract: 
  • The structural transitions required for insulin to activate its receptor and initiate regulation of glucose homeostasis are only partly understood. Here, using ring-closing metathesis, we substitute the A6-A11 disulfide bond of insulin with a rigid, ...

    The structural transitions required for insulin to activate its receptor and initiate regulation of glucose homeostasis are only partly understood. Here, using ring-closing metathesis, we substitute the A6-A11 disulfide bond of insulin with a rigid, non-reducible dicarba linkage, yielding two distinct stereo-isomers (cis and trans). Remarkably, only the cis isomer displays full insulin potency, rapidly lowering blood glucose in mice (even under insulin-resistant conditions). It also posseses reduced mitogenic activity in vitro. Further biophysical, crystallographic and molecular-dynamics analyses reveal that the A6-A11 bond configuration directly affects the conformational flexibility of insulin A-chain N-terminal helix, dictating insulin's ability to engage its receptor. We reveal that in native insulin, contraction of the C α -C α distance of the flexible A6-A11 cystine allows the A-chain N-terminal helix to unwind to a conformation that allows receptor engagement. This motion is also permitted in the cis isomer, with its shorter C α -C α distance, but prevented in the extended trans analogue. These findings thus illuminate for the first time the allosteric role of the A6-A11 bond in mediating the transition of the hormone to an active conformation, significantly advancing our understanding of insulin action and opening up new avenues for the design of improved therapeutic analogues.


    Organizational Affiliation

    University of Melbourne, Department of Medicine, Parkville, Victoria, 3010, Australia.,School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria, 3216, Australia.,College of Medicine & Public Health, Flinders University of South Australia, Bedford Park, 5042, Australia.,College of Medicine & Public Health, Flinders University of South Australia, Bedford Park, 5042, Australia. briony.forbes@flinders.edu.au.,The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria, 3052, Australia.,School of Chemistry, Monash University, Clayton, Victoria, 3800, Australia.,Research School of Chemistry, Australian National University, Acton, ACT 2601, Australia.,School of Chemistry, Monash University, Clayton, Victoria, 3800, Australia. andrea.robinson@monash.edu.,Department of Medical Biology, University of Melbourne, Royal Parade, Parkville, Victoria, 3050, Australia.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Insulin A chain
A, C
21Homo sapiensMutation(s): 2 
Gene Names: INS
Find proteins for P01308 (Homo sapiens)
Go to Gene View: INS
Go to UniProtKB:  P01308
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Insulin B chain
B, D
30Homo sapiensMutation(s): 0 
Gene Names: INS
Find proteins for P01308 (Homo sapiens)
Go to Gene View: INS
Go to UniProtKB:  P01308
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
ABA
Query on ABA
A, C
L-PEPTIDE LINKINGC4 H9 N O2ALA
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.55 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.194 
  • Space Group: P 21 3
Unit Cell:
Length (Å)Angle (°)
a = 77.280α = 90.00
b = 77.280β = 90.00
c = 77.280γ = 90.00
Software Package:
Software NamePurpose
XSCALEdata scaling
PHASERphasing
XDSdata reduction
PHENIXrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2017-12-06
    Type: Initial release
  • Version 1.1: 2018-04-18
    Type: Data collection
  • Version 1.2: 2019-06-19
    Type: Data collection, Database references