Category B. Infectious Diseases and Vaccine Discovery
B1. Characterization of the Hydroxyornithine Transformylase in Pseudomonas aeruginosa
Anindita Basu, Kathleen M. Meneely and Audrey L. Lamb
Molecular Biosciences,Universityof Kansas,1200 Sunnyside Ave,Lawrence,KS 66045
Siderophores are low molecular weight compounds secreted by bacteria in an iron limiting environment. Pseudomonas aeruginosa secretes two types of siderophores, pyoverdin and pyochelin. Other than the role as iron scavenger, pyoverdin is known to regulate the synthesis of a number of virulence factors, which makes it a novel target for drug design. Biosynthesis of pyoverdin is initiated by two enzymes PvdA, a flavin monooxygenase, and PvdF, a hydroxyornithine transformylase. PvdF is involved in the second step of pyoverdin synthesis, converting hydroxyornithine to formylhydroxyornithine using the cofactor 10-formyl-tetrahydrofolate. Characterization of PvdF is being carried out using X-ray crystallography and kinetic assays. Recently, a 2.96 Å diffraction data set was obtained for apo-PvdF.
B2. Structural and functional analyses support that Chlamydia trachomatis protein CT009 is a homolog to the key morphogenesis component RodZ
Kyle E. Kemege, John Hickey, Scott Lovell, Kevin Battaile and P. Scott Hefty
Department of Molecular Biosciences, University of Kansas, Lawrence, KS
Cell division in Chlamydiae is poorly understood as apparent homologs to most conserved bacterial cell division proteins are lacking and, as recent evidence suggests, non-canonical mechanisms may be employed for these processes. Specifically, the rod-cell shape determining protein MreB may be playing a role in chlamydial cell division. In other organisms, MreB is part of a morphogenic complex that requires RodZ for proper morphogenesis. A RodZ homolog was not evident in the chlamydial genomes; however, computational structure modeling (I-TASSER) indicated that uncharacterized ORF CT009 shares structural similarity to RodZ. The X-ray crystal structure of CT009 was solved and validated the accuracy of the I-TASSER predicted structure as well as similarity to RodZ. CT009 and MreB were demonstrated to interact and require two conserved residues in CT009. CT009 expressed in a rodZ deficient E. coli strain restored wild-type rod shaped morphology, also dependent on these key residues. These observations demonstrate that CT009 is a RodZ homolog in Chlamydia and expected to be involved in cell division and septum formation processes in chlamydial species. Furthermore, CT009 sequence similarity analysis supports that many other uncharacterized proteins are likely RodZ homologs.
B3. Discovery and development of highly potent inhibitors of Mycobacterium tuberculosis growth in vitro
Warren S. Weiner,a Frank Schoenen,a Apurba Dutta,a Jeffrey Aubé,a,b E. Lucile White,c Clinton Maddox,c Ntsang Miranda Nebane,c Nichole A. Tower,c Sara McKellip,c Anna Manuvakhova,c Lakshmi Reddy,c Melinda Sosa,c Lynn Rasmussen,c Kanupriya Whig,c Subramaniam Ananthan,c Shichun Lun,d and William Bishaid
aUniversity of Kansas Specialized Chemistry Center, University of Kansas, Lawrence, KS 66047
bDepartment of Medicinal Chemistry, University of Kansas, Lawrence, KS 66047
cSouthern Research Molecular Libraries Screening Center, Southern Research Institute, Birmingham, AL 35205
dCenter for Tuberculosis Research, Division of Infectious Diseases, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21231
Tuberculosis (TB) is a bacterial disease infecting over 2 billion people and is caused by Mycobacterium tuberculosis (M. tb). HTS identified a number of novel scaffolds with antitubercular activity. Here we report the medicinal chemistry efforts on a scaffold leading to highly active small molecules with low nanomolar activity against M. tb in vitro and very low general cytotoxicity.