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PDBsum entry 1lkq

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protein Protein-protein interface(s) links
Hormone/growth factor PDB id
1lkq
Jmol
Contents
Protein chains
21 a.a.
30 a.a. *
* Residue conservation analysis
PDB id:
1lkq
Name: Hormone/growth factor
Title: Nmr structure of human insulin mutant ile-a2-gly, val-a3- gly, his-b10-asp, pro-b28-lys, lys-b29-pro, 20 structures
Structure: Insulin. Chain: a. Engineered: yes. Mutation: yes. Other_details: insulin a chain (residues 90-110). Insulin. Chain: b. Engineered: yes. Mutation: yes.
Source: Synthetic: yes. Other_details: the peptide was chemically synthesized. The sequence of the peptide is naturally found in homo sapiens (human).. (Human).
NMR struc: 20 models
Authors: M.A.Weiss,Q.X.Hua,Y.C.Chu,W.Jia,N.F.Philips,R.Y.Wang, P.G.Katsoyannis
Key ref:
Q.X.Hua et al. (2002). Mechanism of insulin chain combination. Asymmetric roles of A-chain alpha-helices in disulfide pairing. J Biol Chem, 277, 43443-43453. PubMed id: 12196530 DOI: 10.1074/jbc.M206107200
Date:
25-Apr-02     Release date:   22-May-02    
PROCHECK
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 Headers
 References

Protein chain
Pfam   ArchSchema ?
P01308  (INS_HUMAN) -  Insulin
Seq:
Struc:
110 a.a.
21 a.a.*
Protein chain
Pfam   ArchSchema ?
P01308  (INS_HUMAN) -  Insulin
Seq:
Struc:
110 a.a.
30 a.a.*
Key:    PfamA domain  Secondary structure
* PDB and UniProt seqs differ at 5 residue positions (black crosses)

 

 
DOI no: 10.1074/jbc.M206107200 J Biol Chem 277:43443-43453 (2002)
PubMed id: 12196530  
 
 
Mechanism of insulin chain combination. Asymmetric roles of A-chain alpha-helices in disulfide pairing.
Q.X.Hua, Y.C.Chu, W.Jia, N.F.Phillips, R.Y.Wang, P.G.Katsoyannis, M.A.Weiss.
 
  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.
 
  Selected figure(s)  
 
Figure 1.
Fig. 1. Structure and sequence of insulin. A, ribbon model of T-state crystallographic protomer (2-zinc molecule 1, Chinese nomenclature; accession code 4INS) (3). The A chain is shown in red and B chain in blue. Location of side chains Ile^A2 (black), LeuA16 (purple), TyrA19 (red), and disulfide bridges are as indicated (sulfur atoms as orange spheres). B, sequences of insulin A chains. Residues A1-A5 are highlighted in red. Invariant leucine at position A16 is boxed in purple (arrow). Cysteines are shown in boldface. C, crystal structure of insulin (stereo pair) highlighting local structure in neighborhood of LeuA16. The A chain is shown in black and B chain in blue. Labeled residues are color-coded as follows: LeuA16 (red; methyl groups are indicated by red balls), Ile^A2 (purple), disulfide bridges (orange; cysteines are depicted as balls), TyrA19 (purple), and other core residues (green; LeuA13, LeuB11, LeuB15, and ValB18).
Figure 6.
Fig. 6. Summary of sequential 1H NMR assignment in Wüthrich format. Connectivities in A and B chains are outlined in upper and lower panels, respectively. Absence of (i, i + 3) NOEs in A1-A8 segment indicates unraveling of helix. Asterisks indicate sites of glycine substitution at residues A2 and A3. Arrows denote "DKP" substitutions in B chain that prevent self-association (21, 56).
 
  The above figures are reprinted by permission from the ASBMB: J Biol Chem (2002, 277, 43443-43453) copyright 2002.  
  Figures were selected by an automated process.  

Literature references that cite this PDB file's key reference

  PubMed id Reference
20724178 M.Liu, I.Hodish, L.Haataja, R.Lara-Lemus, G.Rajpal, J.Wright, and P.Arvan (2010).
Proinsulin misfolding and diabetes: mutant INS gene-induced diabetes of youth.
  Trends Endocrinol Metab, 21, 652-659.  
19395706 M.A.Weiss (2009).
Proinsulin and the genetics of diabetes mellitus.
  J Biol Chem, 284, 19159-19163.  
19850922 M.Liu, Z.L.Wan, Y.C.Chu, H.Aladdin, B.Klaproth, M.Choquette, Q.X.Hua, R.B.Mackin, J.S.Rao, P.De Meyts, P.G.Katsoyannis, P.Arvan, and M.A.Weiss (2009).
Crystal structure of a "nonfoldable" insulin: impaired folding efficiency despite native activity.
  J Biol Chem, 284, 35259-35272.
PDB code: 3gky
19321436 Q.X.Hua, B.Xu, K.Huang, S.Q.Hu, S.Nakagawa, W.Jia, S.Wang, J.Whittaker, P.G.Katsoyannis, and M.A.Weiss (2009).
Enhancing the activity of a protein by stereospecific unfolding: conformational life cycle of insulin and its evolutionary origins.
  J Biol Chem, 284, 14586-14596.
PDB codes: 2k91 2k9r
18332129 Q.X.Hua, S.H.Nakagawa, W.Jia, K.Huang, N.B.Phillips, S.Q.Hu, and M.A.Weiss (2008).
Design of an active ultrastable single-chain insulin analog: synthesis, structure, and therapeutic implications.
  J Biol Chem, 283, 14703-14716.
PDB codes: 2jzq 3bxq
18492668 Z.L.Wan, K.Huang, S.Q.Hu, J.Whittaker, and M.A.Weiss (2008).
The structure of a mutant insulin uncouples receptor binding from protein allostery. An electrostatic block to the TR transition.
  J Biol Chem, 283, 21198-21210.  
17716170 M.Koch, F.F.Schmid, V.Zoete, and M.Meuwly (2006).
Insulin: a model system for nanomedicine?
  Nanomed, 1, 373-378.  
15705595 M.Liu, Y.Li, D.Cavener, and P.Arvan (2005).
Proinsulin disulfide maturation and misfolding in the endoplasmic reticulum.
  J Biol Chem, 280, 13209-13212.  
16080143 V.Zoete, M.Meuwly, and M.Karplus (2005).
Study of the insulin dimerization: binding free energy calculations and per-residue free energy decomposition.
  Proteins, 61, 79-93.  
15096212 C.Y.Min, Z.S.Qiao, and Y.M.Feng (2004).
Unfolding of human proinsulin. Intermediates and possible role of its C-peptide in folding/unfolding.
  Eur J Biochem, 271, 1737-1747.  
14596591 Z.L.Wan, B.Xu, Y.C.Chu, P.G.Katsoyannis, and M.A.Weiss (2003).
Crystal structure of allo-Ile(A2)-insulin, an inactive chiral analogue: implications for the mechanism of receptor binding.
  Biochemistry, 42, 12770-12783.
PDB codes: 1lw8 1pc1 1q4v
The most recent references are shown first. Citation data come partly from CiteXplore and partly from an automated harvesting procedure. Note that this is likely to be only a partial list as not all journals are covered by either method. However, we are continually building up the citation data so more and more references will be included with time. Where a reference describes a PDB structure, the PDB code is shown on the right.