Structural elucidation of AggR-activated regulator, aar, in enteroaggregative Escherichia coli

Travelers’ Diarrhea is the number one cause of childhood death in the world. Enteroaggregative Escherichia coli (EAEC) is one of the main causes of this disease. EAEC adhere to the surface of the intestine and stack in a brick-like pattern. Via an unstudied quorum-sensing mechanism, these bacteria express a variety of virulence factors that lead to diarrhea. The long-term goal of this research is to elucidate the mechanism by which EAEC changes from benign to virulent. A previously-unstudied open-reading frame in EAEC, AggR activated repressor (Aar), has recently been hypothesized to act as one of the major transcription factors influencing virulence. Here, we describe two viable methods for purification and a method for cleavage. Circular dichroism (CD) data suggests a partially α-helical structure. Further tests, including multi-dimensional NMR and X-ray crystallography, are currently being conducted to determine the tertiary structure of the protein