β-sheet structures and dimer models of the two major tyrocidines, antimicrobial peptides from Bacillus aneurinolyticus

Gadzikano Munyuki, Graham E. Jackson, Gerhard A. Venter, Katalin E. Kövér, László Szilágyi, Marina Rautenbach, Barbara M. Spathelf, Bhaswati Bhattacharya, David Van Der Spoel

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Abstract

The structures of two major tyrocidines, antibiotic peptides from Bacillus aneurinolyticus, in an aqueous environment were studied using nuclear magnetic resonance spectroscopy, restrained molecular dynamics (MD), circular dichroism, and mass spectrometry. TrcA and TrcC formed β-structures in an aqueous environment. Hydrophobic and hydrophilic residues were not totally separated into nonpolar and polar faces of the peptides, indicating that tyrocidines have low amphipathicity. In all the β-structures, residues Trp 4/Phe4 and Orn9 were on the same face. The ability of the peptides to form dimers in aqueous environment was studied by replica exchange MD simulations. Both peptides readily dimerize, and predominant complex structures were characterized through cluster analysis. The peptides formed dimers by either associating sideways or stacking on top of each other. Dimers formed through sideways association were mainly stabilized by hydrogen bonding, while the other dimers were stabilized by hydrophobic interactions. The ability of tyrocidine peptides to form different types of dimers with different orientations suggests that they can form larger aggregates, as well.

Original languageEnglish
Pages (from-to)7798-7806
Number of pages9
JournalBiochemistry
Volume52
Issue number44
DOIs
Publication statusPublished - Nov 5 2013

ASJC Scopus subject areas

  • Biochemistry

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    Munyuki, G., Jackson, G. E., Venter, G. A., Kövér, K. E., Szilágyi, L., Rautenbach, M., Spathelf, B. M., Bhattacharya, B., & Van Der Spoel, D. (2013). β-sheet structures and dimer models of the two major tyrocidines, antimicrobial peptides from Bacillus aneurinolyticus. Biochemistry, 52(44), 7798-7806. https://doi.org/10.1021/bi401363m