European Biophysics Journal

, Volume 28, Issue 6, pp 499–509 | Cite as

Molecular dynamics simulation of α-melanocyte stimulating hormone in a water-membrane model interface

  • Pedro Geraldo Pascutti
  • Lea Jaccoud El-Jaik
  • Paulo Mascarello Bisch
  • Kleber Carlos Mundim
  • Amando Siuiti Ito

Abstract

The conformation of the tridecapeptide α-melanocyte stimulating hormone in the presence of a double water-membrane interface was studied by molecular dynamics simulation, using the computational package THOR. In this program the solvent is represented by a continuous medium with dielectric constant ɛ, and the interface between different media is simulated by a surface of discontinuity of the dielectric constant. The electrostatic image method was used to write down the terms, added to the force field, that describe the polarisation effects induced in the interface by the atomic charges. The program was further improved by the introduction of a second surface, parallel to the first one, to mimic the membrane. A conformational search using the software Prelude was employed to find an initial geometry for the peptide in water. The molecular dynamics simulation performed during 10 ns showed that the peptide structure is flexible in water, without stabilisation of any preferential conformation. In the presence of the model membrane, the peptide moved to the medium representing the interior of the membrane. Inside the low dielectric constant medium, the structure of the peptide showed a turn in the central sequence of amino acids and a packed conformation remained stabilised during more than 7.0 ns of simulation.

Key words Melanotropic peptides Peptide-lipid interaction Dielectric discontinuity Molecular dynamics Electrostatic image method 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • Pedro Geraldo Pascutti
    • 1
  • Lea Jaccoud El-Jaik
    • 2
  • Paulo Mascarello Bisch
    • 1
  • Kleber Carlos Mundim
    • 3
  • Amando Siuiti Ito
    • 4
  1. 1.Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, BrazilBR
  2. 2.Centro Brasileiro de Pesquisas Físicas, BrazilBR
  3. 3.Universidade Federal da Bahia, BrazilBR
  4. 4.Instituto de Física, Universidade de São Paulo, Caixa Postal 66318, 05315-970 São Paulo, SP, Brazil e-mail: amando@fge.if.usp.brBR

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