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


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Submitted: 20 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


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

  • DOI: 10.1006/jmbi.1997.1574
  • Primary Citation of Related Structures:  
    1SJU, 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 ...

    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.


    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:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
PROINSULIN A50Homo sapiensMutation(s): 2 
Gene Names: INS
Find proteins for P01308 (Homo sapiens)
Explore P01308 
Go to UniProtKB:  P01308
NIH Common Fund Data Resources
PHAROS:  P01308
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

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

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

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