Opposites Attract: Heptosyltransferase I Conformational Changes Induced by Interactions between the Substrate and Positively Charged Residues.

Gram-negative bacterial viability is greatly reduced by the disruption of heptose sugar addition during the biosynthesis of lipopolysaccharide (LPS), an important bacterial outer membrane component. Heptosyltransferase I (HepI), a member of the GT-B structural subclass of glycosyltransferases, is therefore an essential enzyme for the biosynthesis of the LPS. The disruption of HepI also increases the susceptibility of bacteria to hydrophobic antibiotics, making HepI a potential target for drug development.

Hydrophobic interactions of sucralose with protein structures.

Sucralose is a commonly employed artificial sweetener that appears to destabilize protein native structures. This is in direct contrast to the bio-preservative nature of its natural counterpart, sucrose, which enhances the stability of biomolecules against environmental stress. We have further explored the molecular interactions of sucralose as compared to sucrose to illuminate the origin of the differences in their bio-preservative efficacy.