Journal of Glycobiology
Open Access

Conformational properties of the antigenic determinant of a Salmonella polysaccharide using enhanced sampling MD simulations

Glycobiology World Congress

August 10-12, 2015 Philadelphia, USA

Alexander D MacKerell

Posters-Accepted Abstracts: J Glycobiol

Abstract :

Salmonella infection is a common bacterial disease that causes approximately 1.2 million illnesses in the US according to the
Centers for Disease Control and Prevention. Antibodies targeting the O-antigen of Salmonella can mediate bacterial killing
and thus vaccine development has been investigated using O-polysaccharide conjugates. The O-antigen consists of multiple
repeating units of tetrasaccharide, [(3)-D-Galp--(12)[D-Abep--(13)]-D-Manp--(14)-D-Rhap--(1]n. To provide more insights
on the structural features of this polysaccharide and potentially facilitate the design of more potent vaccines, we studied the
conformational preference of the O-polysaccharide with 3 repeating units in the absence and presence of the bound antibody or
with O-acetylation at the C2 position of Abep and Rhap residues using the CHARMM36 force field with the recently developed
replica exchange with concurrent solute scaling and Hamiltonian biasing method. Results suggest preferred conformations
existing in different conditions the may be related to the antigenic potential of the polysaccharide.