PDBsum entry 4efx

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protein metals Protein-protein interface(s) links
Hormone PDB id
Protein chains
21 a.a.
28 a.a.
_ZN ×2
Waters ×33
PDB id:
Name: Hormone
Title: Highly biologically active insulin with additional disulfide
Structure: Insulin. Chain: a, c. Synonym: insulin a chain. Engineered: yes. Mutation: yes. Insulin. Chain: b, d. Synonym: insulin b chain. Engineered: yes
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: ins. Expressed in: saccharomyces cerevisiae. Expression_system_taxid: 4932. Expression_system_taxid: 4932
1.98Å     R-factor:   0.210     R-free:   0.278
Authors: M.Norrman,T.N.Vinther
Key ref: T.N.Vinther et al. (2013). Insulin analog with additional disulfide bond has increased stability and preserved activity. Protein Sci, 22, 296-305. PubMed id: 23281053 DOI: 10.1002/pro.2211
30-Mar-12     Release date:   06-Mar-13    
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Protein chains
Pfam   ArchSchema ?
P01308  (INS_HUMAN) -  Insulin
110 a.a.
21 a.a.*
Protein chains
Pfam   ArchSchema ?
P01308  (INS_HUMAN) -  Insulin
110 a.a.
28 a.a.*
Key:    PfamA domain  Secondary structure
* PDB and UniProt seqs differ at 2 residue positions (black crosses)

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


DOI no: 10.1002/pro.2211 Protein Sci 22:296-305 (2013)
PubMed id: 23281053  
Insulin analog with additional disulfide bond has increased stability and preserved activity.
T.N.Vinther, M.Norrman, U.Ribel, K.Huus, M.Schlein, D.B.Steensgaard, T...Pedersen, I.Pettersson, S.Ludvigsen, T.Kjeldsen, K.J.Jensen, F.Hubálek.
Insulin is a key hormone controlling glucose homeostasis. All known vertebrate insulin analogs have a classical structure with three 100% conserved disulfide bonds that are essential for structural stability and thus the function of insulin. It might be hypothesized that an additional disulfide bond may enhance insulin structural stability which would be highly desirable in a pharmaceutical use. To address this hypothesis, we designed insulin with an additional interchain disulfide bond in positions A10/B4 based on Cα-Cα distances, solvent exposure, and side-chain orientation in human insulin (HI) structure. This insulin analog had increased affinity for the insulin receptor and apparently augmented glucodynamic potency in a normal rat model compared with HI. Addition of the disulfide bond also resulted in a 34.6°C increase in melting temperature and prevented insulin fibril formation under high physical stress even though the C-terminus of the B-chain thought to be directly involved in fibril formation was not modified. Importantly, this analog was capable of forming hexamer upon Zn addition as typical for wild-type insulin and its crystal structure showed only minor deviations from the classical insulin structure. Furthermore, the additional disulfide bond prevented this insulin analog from adopting the R-state conformation and thus showing that the R-state conformation is not a prerequisite for binding to insulin receptor as previously suggested. In summary, this is the first example of an insulin analog featuring a fourth disulfide bond with increased structural stability and retained function.