Molecular Recognition in Biological Systems and Bioinformatics

Shown is the structure of a homodimer of the EntB protein, an NRPS involved in the synthesis of the E. coli siderophore (iron chelator) called enterobactin. The larger central domains catalyze a chemical step in the synthesis of the enterobactin precursor, 2,3-dihydroxybenzoic acid. The outer red domains serve as a carrier domain on which a portion of the enterobactin molecule is covalently bound while it is transported to and from different catalytic domains.

Structural Biology; X-ray Crystallography; Enzyme Mechanisms; Multi-domain protein structure; Siderophore biosynthesis; Non-Ribosomal Peptide Synthesis; Natural Product Biosynthesis.

Work in our lab uses X-ray crystallography and functional biochemistry to determine how enzymes function at a molecular level. A complete understanding of the ways that enzymes are able to catalyze chemical reactions is both interesting and raises the possibility of designing new enzymes to perform additional chemical reactions. Our work provides atomic resolution details concerning the role of specific residues in an enzyme active site.

The proteins that we are studying are primarily bacterial proteins that either show novel biochemical properties, making them interesting examples of the how enzymes have evolved to function efficiently, or are essential proteins that may be targets for antibiotic development. An inhibitor that blocks a step that is essential for bacterial growth or virulence may be a lead compound for a novel antibiotic. In particular, we are focused on a family of proteins called non-ribosomal peptide synthetases and the proteins that work with them in the production of peptide antibiotics and peptide siderophores.

X-ray diffraction equipment is available at HWI but would strictly be for use as a collaborative resource with an HWI lab.

• E. coli
• Pseudomonas aeruginosa
• Acinetobacter baumanii

• Non-ribosomal peptide synthetases
• Adenylate-forming enzymes
• Acyl-CoA synthetases and ligases

Many of the proteins that we are studying can serve as targets for antibiotic development as they are important pathways for the bacterial growth and for establishment of an infection.

• Protein expression and purification
• Crystallization
• Structure determination and analysis

The siderophore synthetic pathways from Pseudomonas aeruginosa are being targeted for structural and functional studies because of their relevance to Cystic Fibrosis. Additionally, we have recently determined the structure of a protein involved in siderophore synthesis for the organism, Acinetobacter baumanii, a common pathogen in hospital acquired infections.

http://labs.hwi.buffalo.edu/gulick/pubs.html