Macromolecule Content

• Total Structure Weight: 5.70 kDa 
• Atom Count: 396 
• Residue Count: 51 
• Unique protein chains: 2

1LKQ

NMR STRUCTURE OF HUMAN INSULIN MUTANT ILE-A2-GLY, VAL-A3-GLY, HIS-B10-ASP, PRO-B28-LYS, LYS-B29-PRO, 20 STRUCTURES

• DOI: 10.2210/pdb1LKQ/pdb
• BMRB: 1344

• Classification: HORMONE/GROWTH FACTOR
• Mutation(s): Yes 


• Deposited: 2002-04-25 Released: 2002-05-22 
• Deposition Author(s): Weiss, M.A., Hua, Q.X., Chu, Y.C., Jia, W., Philips, N.F., Wang, R.Y., Katsoyannis, P.G.

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Experimental Data Snapshot

• Method: SOLUTION NMR
• Conformers Calculated: 35 
• Conformers Submitted: 20 
• Selection Criteria: structures with the lowest energy 

Literature

Mechanism of insulin chain combination. Asymmetric roles of A-chain alpha-helices in disulfide pairing

Hua, Q.X., Chu, Y.C., Jia, W., Phillips, N.F., Wang, R.Y., Katsoyannis, P.G., Weiss, M.A.

(2002) J Biol Chem 277: 43443-43453

• PubMed: 12196530 
• DOI: 10.1074/jbc.M206107200
• Primary Citation of Related Structures:  
  1LKQ


• PubMed Abstract: 
  

The A and B chains of insulin combine to form native disulfide bridges without detectable isomers. The fidelity of chain combination thus recapitulates the folding of proinsulin, a precursor protein in which the two chains are tethered by a disordered connecting peptide. We have recently shown that chain combination is blocked by seemingly conservative substitutions in the C-terminal alpha-helix of the A chain. Such analogs, once formed, nevertheless retain high biological activity. By contrast, we demonstrate here that chain combination is robust to non-conservative substitutions in the N-terminal alpha-helix. Introduction of multiple glycine substitutions into the N-terminal segment of the A chain (residues A1-A5) yields analogs that are less stable than native insulin and essentially without biological activity. (1)H NMR studies of a representative analog lacking invariant side chains Ile(A2) and Val(A3) (A chain sequence GGGEQCCTSICSLYQLENYCN; substitutions are italicized and cysteines are underlined) demonstrate local unfolding of the A1-A5 segment in an otherwise native-like structure. That this and related partial folds retain efficient disulfide pairing suggests that the native N-terminal alpha-helix does not participate in the transition state of the reaction. Implications for the hierarchical folding mechanisms of proinsulin and insulin-like growth factors are discussed.

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Organizational Affiliation: 

Department of Biochemistry, Case Western Reserve School of Medicine, Cleveland, Ohio 44106-4935, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
INSULIN	A	21	N/A	Mutation(s): 2
Find proteins for P01308 (Homo sapiens) Explore P01308  Go to UniProtKB:  P01308
NIH Common Fund Data Resources
PHAROS:  P01308

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
INSULIN	B	30	N/A	Mutation(s): 3
Find proteins for P01308 (Homo sapiens) Explore P01308  Go to UniProtKB:  P01308
NIH Common Fund Data Resources
PHAROS:  P01308

Experimental Data & Validation

Experimental Data

• Method: SOLUTION NMR
• Conformers Calculated: 35 
• Conformers Submitted: 20 
• Selection Criteria: structures with the lowest energy 
• OLDERADO: 1LKQ Olderado

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2002-04-25 
• Released Date: 2002-05-22 
Deposition Author(s): Weiss, M.A., Hua, Q.X., Chu, Y.C., Jia, W., Philips, N.F., Wang, R.Y., Katsoyannis, P.G.

Revision History 

• Version 1.0: 2002-05-22
  Type: Initial release
  
• Version 1.1: 2008-04-28
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance