4IUZ

High resolution crystal structure of racemic ester insulin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.221 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Fully Convergent Chemical Synthesis of Ester Insulin: Determination of the High Resolution X-ray Structure by Racemic Protein Crystallography.

Avital-Shmilovici, M.Mandal, K.Gates, Z.P.Phillips, N.B.Weiss, M.A.Kent, S.B.

(2013) J.Am.Chem.Soc. 135: 3173-3185

  • DOI: 10.1021/ja311408y

  • PubMed Abstract: 
  • Efficient total synthesis of insulin is important to enable the application of medicinal chemistry to the optimization of the properties of this important protein molecule. Recently we described "ester insulin"--a novel form of insulin in which the f ...

    Efficient total synthesis of insulin is important to enable the application of medicinal chemistry to the optimization of the properties of this important protein molecule. Recently we described "ester insulin"--a novel form of insulin in which the function of the 35 residue C-peptide of proinsulin is replaced by a single covalent bond--as a key intermediate for the efficient total synthesis of insulin. Here we describe a fully convergent synthetic route to the ester insulin molecule from three unprotected peptide segments of approximately equal size. The synthetic ester insulin polypeptide chain folded much more rapidly than proinsulin, and at physiological pH. Both the D-protein and L-protein enantiomers of monomeric DKP ester insulin (i.e., [Asp(B10), Lys(B28), Pro(B29)]ester insulin) were prepared by total chemical synthesis. The atomic structure of the synthetic ester insulin molecule was determined by racemic protein X-ray crystallography to a resolution of 1.6 Å. Diffraction quality crystals were readily obtained from the racemic mixture of {D-DKP ester insulin + L-DKP ester insulin}, whereas crystals were not obtained from the L-ester insulin alone even after extensive trials. Both the D-protein and L-protein enantiomers of monomeric DKP ester insulin were assayed for receptor binding and in diabetic rats, before and after conversion by saponification to the corresponding DKP insulin enantiomers. L-DKP ester insulin bound weakly to the insulin receptor, while synthetic L-DKP insulin derived from the L-DKP ester insulin intermediate was fully active in binding to the insulin receptor. The D- and L-DKP ester insulins and D-DKP insulin were inactive in lowering blood glucose in diabetic rats, while synthetic L-DKP insulin was fully active in this biological assay. The structural basis of the lack of biological activity of ester insulin is discussed.


    Organizational Affiliation

    Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Insulin A chain
A
21Homo sapiensMutation(s): 0 
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
30Homo sapiensMutation(s): 3 
Gene Names: INS
Find proteins for P01308 (Homo sapiens)
Go to Gene View: INS
Go to UniProtKB:  P01308
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GOL
Query on GOL

Download SDF File 
Download CCD File 
B
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
PEG
Query on PEG

Download SDF File 
Download CCD File 
B
DI(HYDROXYETHYL)ETHER
C4 H10 O3
MTHSVFCYNBDYFN-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.6 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.221 
  • Space Group: P -1
Unit Cell:
Length (Å)Angle (°)
a = 20.495α = 96.42
b = 27.757β = 98.60
c = 34.765γ = 104.46
Software Package:
Software NamePurpose
MOLREPphasing
PDB_EXTRACTdata extraction
HKL-2000data scaling
HKL-2000data reduction
REFMACrefinement
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-02-13
    Type: Initial release
  • Version 1.1: 2013-03-20
    Type: Database references