PDBsum entry 1sf1

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Hormone/growth factor PDB id
Protein chains
21 a.a.
30 a.a. *
* Residue conservation analysis
PDB id:
Name: Hormone/growth factor
Title: Nmr structure of human insulin under amyloidogenic condition, 15 structures
Structure: Insulin a chain. Chain: a. Engineered: yes. Insulin. Chain: b. Engineered: yes
Source: Homo sapiens. Human. Organism_taxid: 9606. Expressed in: escherichia coli. Expression_system_taxid: 562. Gene: ins. Expression_system_taxid: 562
NMR struc: 15 models
Authors: M.A.Weiss,Q.X.Hua
Key ref:
Q.X.Hua and M.A.Weiss (2004). Mechanism of insulin fibrillation: the structure of insulin under amyloidogenic conditions resembles a protein-folding intermediate. J Biol Chem, 279, 21449-21460. PubMed id: 14988398 DOI: 10.1074/jbc.M314141200
19-Feb-04     Release date:   30-Mar-04    
Go to PROCHECK summary

Protein chain
Pfam   ArchSchema ?
P01308  (INS_HUMAN) -  Insulin
110 a.a.
21 a.a.
Protein chain
Pfam   ArchSchema ?
P01308  (INS_HUMAN) -  Insulin
110 a.a.
30 a.a.
Key:    PfamA domain  Secondary structure

 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     extracellular region   1 term 
  Biochemical function     hormone activity     1 term  


DOI no: 10.1074/jbc.M314141200 J Biol Chem 279:21449-21460 (2004)
PubMed id: 14988398  
Mechanism of insulin fibrillation: the structure of insulin under amyloidogenic conditions resembles a protein-folding intermediate.
Q.X.Hua, M.A.Weiss.
Insulin undergoes aggregation-coupled misfolding to form a cross-beta assembly. Such fibrillation has long complicated its manufacture and use in the therapy of diabetes mellitus. Of interest as a model for disease-associated amyloids, insulin fibrillation is proposed to occur via partial unfolding of a monomeric intermediate. Here, we describe the solution structure of human insulin under amyloidogenic conditions (pH 2.4 and 60 degrees C). Use of an enhanced sensitivity cryogenic probe at high magnetic field avoids onset of fibrillation during spectral acquisition. A novel partial fold is observed in which the N-terminal segments of the A- and B-chains detach from the core. Unfolding of the N-terminal alpha-helix of the A-chain exposes a hydrophobic surface formed by native-like packing of the remaining alpha-helices. The C-terminal segment of the B-chain, although not well ordered, remains tethered to this partial helical core. We propose that detachment of N-terminal segments makes possible aberrant protein-protein interactions in an amyloidogenic nucleus. Non-cooperative unfolding of the N-terminal A-chain alpha-helix resembles that observed in models of proinsulin folding intermediates and foreshadows the extensive alpha --> beta transition characteristic of mature fibrils.
  Selected figure(s)  
Figure 1.
FIG. 1. Schematic mechanism of insulin fibrillation providing a general kinetic scheme (A) and representative insulin structures (B). A, proposed pathway of insulin fibrillation via partial unfolding of the monomer (10, 48, 51). The native state is protected by classical self-assembly (far left). Disassembly leads to an equilibrium between native and partially folded monomers (open triangle and red trapezoid, respectively). The putative partial fold may unfold completely as an off-pathway event (open circle) or aggregate to form a nucleus en route to a protofilament (far right). B, corresponding structures of the insulin fibrillation process at pH 2. Crystal structure of native-like insulin dimer is shown at the far left (28; Protein Data Bank accession number 1GUJ [PDB] ). The A-chain is shown in green and the B-chain in blue. Models of hypothesized amyloidogenic intermediate (at 60 °C prior to onset of fibrillation) and nucleus are shown at the center; cylinder model is based on the present results (see Fig. 9). Cylinders and arrow indicate temperature-stable substructure (residues B9-B26 and A16-A20). Dashed lines indicate disordered regions. The three disulfide bridges of the protein are indicated in schematic form by balls (sulfur atoms). Color scheme follows that of dimer at the far left. Proposed low-resolution model of insulin fibril (11) is shown at the far right.
Figure 8.
FIG. 8. Comparison of NOESY spectra of insulin in aqueous solution at pH 2.4 and 60 °C obtained at 600 MHz using Bruker cryo-probe (A and C) relative to native-like spectrum in 20% deuterated acetic acid at pH 1.9 and 32 °C (B and D). NOEs between aromatic protons and methyl resonances in C and D are: a, B16 H[ ]-B12 [1]-CH[3]; b, B16 H[ ]-B12 [2]-CH[3]; c, A19 H[ ]-A16 [1,2]-CH[3]; d, B16 H[ ]-B12 [1]-CH[3]; e, B16 H[ ]-B12 [2]-CH[3]; f, B24 H[ ]-B15 [1]-CH[3]; g, A19 H[ ]-A16 [1,2]-CH[3]; and h, A19 H[ ]-B15 [1]-CH[3]. Panels A and B are corresponding aromatic regions. The reduction in chemical shift dispersion among aromatic resonances at 60 °C (A) relative to dispersion at 25 °C (B) is evident.
  The above figures are reprinted by permission from the ASBMB: J Biol Chem (2004, 279, 21449-21460) copyright 2004.  
  Figures were selected by an automated process.  

Literature references that cite this PDB file's key reference

  PubMed id Reference
21207612 Y.Singh, P.C.Sharpe, H.N.Hoang, A.J.Lucke, A.W.McDowall, S.P.Bottomley, and D.P.Fairlie (2011).
Amyloid formation from an α-helix peptide bundle is seeded by 3(10)-helix aggregates.
  Chemistry, 17, 151-160.  
19810108 Y.F.Lin, J.H.Zhao, H.L.Liu, K.T.Liu, J.T.Chen, W.B.Tsai, and Y.Ho (2010).
Structural stability and aggregation behavior of the VEALYL peptide derived from human insulin: a molecular dynamics simulation study.
  Biopolymers, 94, 269-278.  
20336256 Z.Ganim, K.C.Jones, and A.Tokmakoff (2010).
Insulin dimer dissociation and unfolding revealed by amide I two-dimensional infrared spectroscopy.
  Phys Chem Chem Phys, 12, 3579-3588.  
20006956 J.H.Choi, B.C.May, H.Wille, and F.E.Cohen (2009).
Molecular modeling of the misfolded insulin subunit and amyloid fibril.
  Biophys J, 97, 3187-3195.  
19533727 J.Haas, E.Vöhringer-Martinez, A.Bögehold, D.Matthes, U.Hensen, A.Pelah, B.Abel, and H.Grubmüller (2009).
Primary steps of pH-dependent insulin aggregation kinetics are governed by conformational flexibility.
  Chembiochem, 10, 1816-1822.  
19317567 L.Prieto, and A.Rey (2009).
Topology-based potentials and the study of the competition between protein folding and aggregation.
  J Chem Phys, 130, 115101.  
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
18946870 R.Ramachandran, W.Paul, and C.P.Sharma (2009).
Synthesis and characterization of PEGylated calcium phosphate nanoparticles for oral insulin delivery.
  J Biomed Mater Res B Appl Biomater, 88, 41-48.  
19438709 W.Cui, J.W.Ma, P.Lei, W.H.Wu, Y.P.Yu, Y.Xiang, A.J.Tong, Y.F.Zhao, and Y.M.Li (2009).
Insulin is a kinetic but not a thermodynamic inhibitor of amylin aggregation.
  FEBS J, 276, 3365-3371.  
17497735 W.Paul, and C.P.Sharma (2008).
Tricalcium phosphate delayed release formulation for oral delivery of insulin: A proof-of-concept study.
  J Pharm Sci, 97, 863-870.  
17472440 B.Vestergaard, M.Groenning, M.Roessle, J.S.Kastrup, M.van de Weert, J.M.Flink, S.Frokjaer, M.Gajhede, and D.I.Svergun (2007).
A helical structural nucleus is the primary elongating unit of insulin amyloid fibrils.
  PLoS Biol, 5, e134.  
17847076 Z.Q.Wen (2007).
Raman spectroscopy of protein pharmaceuticals.
  J Pharm Sci, 96, 2861-2878.  
16239333 A.Podestà, G.Tiana, P.Milani, and M.Manno (2006).
Early events in insulin fibrillization studied by time-lapse atomic force microscopy.
  Biophys J, 90, 589-597.  
16969698 K.Huus, S.Havelund, H.B.Olsen, M.van de Weert, and S.Frokjaer (2006).
Chemical and thermal stability of insulin: effects of zinc and ligand binding to the insulin zinc-hexamer.
  Pharm Res, 23, 2611-2620.  
16581839 M.Manno, E.F.Craparo, V.Martorana, D.Bulone, and P.L.San Biagio (2006).
Kinetics of insulin aggregation: disentanglement of amyloid fibrillation from large-size cluster formation.
  Biophys J, 90, 4585-4591.  
16272434 R.F.Pasternack, E.J.Gibbs, S.Sibley, L.Woodard, P.Hutchinson, J.Genereux, and K.Kristian (2006).
Formation kinetics of insulin-based amyloid gels and the effect of added metalloporphyrins.
  Biophys J, 90, 1033-1042.  
16597825 T.J.Gibson, and R.M.Murphy (2006).
Inhibition of insulin fibrillogenesis with targeted peptides.
  Protein Sci, 15, 1133-1141.  
15596515 M.R.Krebs, E.H.Bromley, S.S.Rogers, and A.M.Donald (2005).
The mechanism of amyloid spherulite formation by bovine insulin.
  Biophys J, 88, 2013-2021.  
15574704 R.Jansen, W.Dzwolak, and R.Winter (2005).
Amyloidogenic self-assembly of insulin aggregates probed by high resolution atomic force microscopy.
  Biophys J, 88, 1344-1353.  
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 codes are shown on the right.