Analysis study on the dimerization requirements of the Staphylococcus aureus type VII secretion system components EsxB and EsxD / Amany Maged Ibrahim ; Supervised Mohammed Abdelhalim Ramadan , Yasser M. Ragab , Khaled Ahmed Aly

Thesis (Ph.D.) - Cairo University - Faculty of Pharmacy - Department of Microbiology and Immunology

Type VII secretion system (T7SS) plays a vital role in bacterial virulence, survival and persistence in tissue hosts. It has been identified in several gram positive bacteria including Staphylococcus aureus and was reported to be involved in persistence of abscess in deep host tissues. Deleting any of the 11 genes comprising staphylococcal T7SS, diminished the abscess in mice renal abscess model. EsxB and EsxD are two T7SS secretory proteins that are known to strongly interact. Using error-prone random PCR mutagenesis coupled with bacterial two-hybrid screening, amino acid number 53; Asparagine, was identified as the interaction domain for EsxB. On the other hand, N-terminal truncations from EsxD followed by bacterial two-hybrid analysis, identified amino acids number 11 to 15 to be involved in dimerization of EsxD with EsxB. Furthermore, copper was found to be crucial for WT EsxB:EsxD interaction, where the interaction was abolished when E.coli DHM1 cells harboring WT EsxB:EsxD were grown in the presence of the specific copper chelator; Ammonium tetra thiomolybdate. Analysis of the dynamics of protein interactions in T7SS is a gateway to discovering novel approaches to neutralize bacterial pathogenesis and virulence, in turn diminishing its effects on host cells

Issued also as CD