A comparison of the dynamic behavior of monomeric and dimeric insulin shows structural rearrangements in the active monomer.

Details

Serval ID
serval:BIB_E601FAC76D2E
Type
Article: article from journal or magazin.
Collection
Publications
Title
A comparison of the dynamic behavior of monomeric and dimeric insulin shows structural rearrangements in the active monomer.
Journal
Journal of molecular biology
Author(s)
Zoete V., Meuwly M., Karplus M.
ISSN
0022-2836 (Print)
ISSN-L
0022-2836
Publication state
Published
Issued date
17/09/2004
Peer-reviewed
Oui
Volume
342
Number
3
Pages
913-929
Language
english
Notes
Publication types: Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, P.H.S.
Publication Status: ppublish
Abstract
Molecular dynamics (MD) simulations (5-10ns in length) and normal mode analyses were performed for the monomer and dimer of native porcine insulin in aqueous solution; both starting structures were obtained from an insulin hexamer. Several simulations were done to confirm that the results obtained are meaningful. The insulin dimer is very stable during the simulation and remains very close to the starting X-ray structure; the RMS fluctuations calculated from the MD simulation agree with the experimental B-factors. Correlated motions were found within each of the two monomers; they can be explained by persistent non-bonded interactions and disulfide bridges. The correlated motions between residues B24 and B26 of the two monomers are due to non-bonded interactions between the side-chains and backbone atoms. For the isolated monomer in solution, the A chain and the helix of the B chain are found to be stable during 5ns and 10ns MD simulations. However, the N-terminal and the C-terminal parts of the B chain are very flexible. The C-terminal part of the B chain moves away from the X-ray conformation after 0.5-2.5ns and exposes the N-terminal residues of the A chain that are thought to be important for the binding of insulin to its receptor. Our results thus support the hypothesis that, when monomeric insulin is released from the hexamer (or the dimer in our study), the C-terminal end of the monomer (residues B25-B30) is rearranged to allow binding to the insulin receptor. The greater flexibility of the C-terminal part of the beta chain in the B24 (Phe-->Gly) mutant is in accord with the NMR results. The details of the backbone and side-chain motions are presented. The transition between the starting conformation and the more dynamic structure of the monomers is characterized by displacements of the backbone of Phe B25 and Tyr B26; of these, Phe B25 has been implicated in insulin activation.

Keywords
Amino Acid Sequence, Amino Acid Substitution, Animals, Dimerization, Drug Stability, Humans, Hydrogen Bonding, In Vitro Techniques, Insulin/chemistry, Insulin/genetics, Models, Molecular, Molecular Sequence Data, Mutagenesis, Site-Directed, Nuclear Magnetic Resonance, Biomolecular, Protein Structure, Quaternary, Recombinant Proteins/chemistry, Recombinant Proteins/genetics, Solutions, Swine, Thermodynamics
Pubmed
Web of science
Create date
05/02/2018 15:01
Last modification date
20/08/2019 16:09
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