Macromolecule Content

• Total Structure Weight: 5693.45 
• Atom Count: 396 
• Residue Count: 50 
• Unique protein chains: 1

1SJU

MINI-PROINSULIN, SINGLE CHAIN INSULIN ANALOG MUTANT: DES B30, HIS(B 10)ASP, PRO(B 28)ASP AND PEPTIDE BOND BETWEEN LYS B 29 AND GLY A 1, NMR, 20 STRUCTURES

• DOI: 10.2210/pdb1SJU/pdb
• BMRB: 1344

• Classification: HORMONE
• Organism(s): Homo sapiens
• Mutation(s): 2 


• Deposited: 1997-10-09 Released: 1998-03-18 
• Deposition Author(s): Hua, Q.X., Hu, S.Q., Jia, W.H., Chu, Y.C., Burke, G.T., Wang, S.H., Katsoyannis, P.G., Weiss, M.A.

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Experimental Data Snapshot

• Method: SOLUTION NMR
• Conformers Submitted: 20 

Literature

Mini-proinsulin and mini-IGF-I: homologous protein sequences encoding non-homologous structures.

Hua, Q.X., Hu, S.Q., Jia, W., Chu, Y.C., Burke, G.T., Wang, S.H., Wang, R.Y., Katsoyannis, P.G., Weiss, M.A.

(1998) J.Mol.Biol. 277: 103-118

• PubMed: 9514738 
• DOI: 10.1006/jmbi.1997.1574
• Primary Citation of Related Structures:  
  1SJT


• PubMed Abstract: 
  

Protein minimization highlights essential determinants of structure and function. Minimal models of proinsulin and insulin-like growth factor I contain homologous A and B domains as single-chain analogues. Such models (designated mini-proinsulin and mini-IGF-I) have attracted wide interest due to their native foldability but complete absence of biological activity. The crystal structure of mini-proinsulin, determined as a T3R3 hexamer, is similar to that of the native insulin hexamer. Here, we describe the solution structure of a monomeric mini-proinsulin under physiologic conditions and compare this structure to that of the corresponding two-chain analogue. The two proteins each contain substitutions in the B-chain (HisB10-->Asp and ProB28-->Asp) designed to destabilize self-association by electrostatic repulsion; the proteins differ by the presence or absence of a peptide bond between LysB29 and GlyA1. The structures are essentially identical, resembling in each case the T-state crystallographic protomer. Differences are observed near the site of cross-linking: the adjoining A1-A8 alpha-helix (variable among crystal structures) is less well-ordered in mini-proinsulin than in the two-chain variant. The single-chain analogue is not completely inactive: its affinity for the insulin receptor is 1500-fold lower than that of the two-chain analogue. Moreover, at saturating concentrations mini-proinsulin retains the ability to stimulate lipogenesis in adipocytes (native biological potency). These results suggest that a change in the conformation of insulin, as tethered by the B29-A1 peptide bond, optimizes affinity but is not integral to the mechanism of transmembrane signaling. Surprisingly, the tertiary structure of mini-proinsulin differs from that of mini-IGF-I (main-chain rms deviation 4.5 A) despite strict conservation of non-polar residues in their respective hydrophobic cores (side-chain rms deviation 4.9 A). Three-dimensional profile scores suggest that the two structures each provide acceptable templates for threading of insulin-like sequences. Mini-proinsulin and mini-IGF-I thus provide examples of homologous protein sequences encoding non-homologous structures.

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Organizational Affiliation: 

Center for Molecular Oncology and Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL 60637, USA.

Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
PROINSULIN	A	50	Homo sapiens	Mutation(s): 2  Gene Names: INS
Find proteins for P01308 (Homo sapiens) Go to Gene View: INS Go to UniProtKB:  P01308

Experimental Data & Validation

Experimental Data

• Method: SOLUTION NMR
• Conformers Submitted: 20 
• Olderado: 1SJU Olderado

Software Package:

Software Name	Purpose
X-PLOR	model building
X-PLOR	phasing
X-PLOR	refinement

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 1997-10-09 
• Released Date: 1998-03-18 
• Deposition Author(s): Hua, Q.X., Hu, S.Q., Jia, W.H., Chu, Y.C., Burke, G.T., Wang, S.H., Katsoyannis, P.G., Weiss, M.A.

Revision History 

• Version 1.0: 1998-03-18
  Type: Initial release
• Version 1.1: 2008-03-24
  Type: Version format compliance
• Version 1.2: 2011-07-13
  Type: Version format compliance