Research Summary

Understanding the import of sugar molecules by pathogenic bacteria.

Pathogenic bacteria are very clever in using host derived molecules, not only for their growth, but also eluding the host defense mechanism and cause diseases. Sialic acid, a nine carbon sugar, is such a molecule and is found abundantly in humans. Some bacteria can import this sialic acid and utilize as a carbon source for energy production or modify their own outer surface. Sialic acid decorated bacteria will be recognized as “self” by human immune cells and will thrive well. Thus uptake of sialic acid can remarkably increase survival of pathogenic bacteria inside a host.

To import sialic acid, bacteria use specific classes of proteins present in their membranes. I focus on such a class of the membrane proteins which help bacteria in scavenging sialic acid. The main goal is to get a detailed structure of such membrane protein complexes and use that for drug screening. The work can result in new drugs for better treatment of diseases caused by the bacteria.

Figure Legend: Sialic acid transport in bacteria: (A) Bacteria can import sialic acid through proteins present in their membrane. Once internalized, sialic acid can either be used to generate energy, or as a decoration for the bacterial outer surface to evade host immune system. (B) By blocking the membrane transport protein, bacteria will fail to use sialic acid for energy generation or surviving the host defense mechanism. This decreases overall survival fitness of such bacteria inside a host.