Abstract 1587 Crystallization of the Glu467Ala Residue and Its Co-Complex in Desferroxiamine D

Iron chelation has been an issue with pathogenic bacteria and new classes of antibiotics have not been discovered in recent years. While humans use iron for transporting oxygen through the bloodstream, bacteria repurpose it for performing metabolic processes to further infect its host. Antibiotics need to be developed to prevent these virulence factors from taking place and the first step towards this path is uncovering the structure of the NIS synthetases, a pathway used to catalyze the production of the siderophore Desferrioxamine E. To determine how one of the catalytic residues (Glu467Ala) in a precursor (Desferrioxamine D) interacts with the substrate, crystallography screenings were performed to test a wide variety of conditions for complexing substrate and ATP into their respective binding sites. Previous binding studies with E445A complexing two ATP to DesD implied there may be two conformations for hydrolyzing ATP, however, were unable to complex with HSC. One hypothesis implies that complexing both ATPs may reduce the enzyme's affinity for HSC, preventing the binding from taking place. To investigate this, each of the crystals were soaked in high concentrations of HSC and lower concentrations of ATP. The implications of the resulting data sets will be presented at the ASBMB conference. This research was supported in part by the National Science Foundation (NSF-RUI grant 1716986 to K.M.H), the John Stauffer Research Fellows Program, and California Lutheran University.