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 
  • R-Value Observed: 0.195 

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
  • Primary Citation of Related Structures:  
    5T7R

  • 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, non-reducible dicarba linkage, yielding two distinct stereo-isomers (cis and trans) ...

    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: 

    College of Medicine & Public Health, Flinders University of South Australia, Bedford Park, 5042, Australia. briony.forbes@flinders.edu.au.



Macromolecules
Find similar proteins by: 
(by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Insulin A chainA, C21Homo sapiensMutation(s): 2 
Gene Names: INS
UniProt & NIH Common Fund Data Resources
Find proteins for P01308 (Homo sapiens)
Explore P01308 
Go to UniProtKB:  P01308
PHAROS:  P01308
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP01308
Protein Feature View
Expand
  • Reference Sequence
Find similar proteins by: 
(by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Insulin B chainB, D30Homo sapiensMutation(s): 0 
Gene Names: INS
UniProt & NIH Common Fund Data Resources
Find proteins for P01308 (Homo sapiens)
Explore P01308 
Go to UniProtKB:  P01308
PHAROS:  P01308
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP01308
Protein Feature View
Expand
  • Reference Sequence
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 
  • R-Value Observed: 0.195 
  • Space Group: P 21 3
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 77.28α = 90
b = 77.28β = 90
c = 77.28γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
XSCALEdata scaling
PHASERphasing

Structure Validation

View Full Validation Report



View more in-depth experimental data

Entry History 

Deposition Data

Revision History  (Full details and data files)

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