4 research outputs found
β‑Sheet Structures and Dimer Models of the Two Major Tyrocidines, Antimicrobial Peptides from <i>Bacillus aneurinolyticus</i>
The
structures of two major tyrocidines, antibiotic peptides from <i>Bacillus aneurinolyticus</i>, 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<b>-</b>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<sup>4</sup>/Phe<sup>4</sup> and Orn<sup>9</sup> 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