Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

Standalone Viewers  
Protein Workshop | Ligand Explorer

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 2-mer - AB 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 6098.93 
• Atom Count: 445 
• Residue Count: 51 
• Unique protein chains: 2

4IUZ

High resolution crystal structure of racemic ester insulin

• DOI: 10.2210/pdb4IUZ/pdb

• Classification: HORMONE PRECURSOR
• Organism(s): Homo sapiens
• Mutation(s): 3 


• Deposited: 2013-01-22 Released: 2013-02-13 
• Deposition Author(s): Avital-Shmilovici, M., Mandal, K., Gates, Z.P., Phillips, N., Weiss, M.A., Kent, S.B.H.

---

Experimental Data Snapshot

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

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

• PubMed: 23343390 
• 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 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
Molecule	Chains	Sequence Length	Organism	Details
Insulin A chain	A	21	Homo sapiens	Mutation(s): 0  Gene Names: INS
Find proteins for P01308 (Homo sapiens) Go to Gene View: INS Go to UniProtKB:  P01308

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details
Insulin B chain	B	30	Homo sapiens	Mutation(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
ID	Chains	Name / Formula / InChI Key	2D Diagram & Interactions
GOL	B	GLYCEROL GLYCERIN; PROPANE-1,2,3-TRIOL C3 H8 O3 PEDCQBHIVMGVHV-UHFFFAOYSA-N
PEG	B	DI(HYDROXYETHYL)ETHER C4 H10 O3 MTHSVFCYNBDYFN-UHFFFAOYSA-N

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 = 20.495	α = 96.42
b = 27.757	β = 98.60
c = 34.765	γ = 104.46

Software Package:

Software Name	Purpose
MOLREP	phasing
PDB_EXTRACT	data extraction
HKL-2000	data scaling
HKL-2000	data reduction
REFMAC	refinement
SCALEPACK	data scaling

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2013-01-22 
• Released Date: 2013-02-13 
• Deposition Author(s): Avital-Shmilovici, M., Mandal, K., Gates, Z.P., Phillips, N., Weiss, M.A., Kent, S.B.H.

Revision History 

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