Abstract
Trichomonas vaginalis (T. vaginalis), an anaerobic, parasitic flagellated protozoan, is the causative agent of human trichomoniasis, the most common nonviral sexually transmitted infections (STIs) in the world. Cytoadherence, a crucial step for T. vaginalis infection, has been shown to involve multiple surface adhesion proteins. The ap65-1 gene was a member of the ap65 (adhesion protein 65) multigene family encoding multiple homologous 65-kDa proteins. Recently, novel transcription factors, Myb1 and Myb2 proteins, were found to be involved in the transcriptional regulation of ap65-1 gene in T. vaginalis. MRE-1/MRE-2r (which overlap) and MRE-2f, which were found to be the multiple Myb recognition elements, regulate multifarious ap65-1 expression, inferring the involvement of Myb-like transcription factors in the transcription machinery of the parasite.The full-length Myb2 protein encoded by the myb2 gene was found to interact with specific sequence contexts spanning MRE-1 and MRE-2f. The truncated Myb2 protein, Myb2x, spanning amino acid sequence 40-156, has been found to retain similar DNA binding affinity. We have investigated the interactions of Myb2x protein with MRE-2r and MRE-2f by biophysical methods. Moreover, we have determined the structures and dynamics of Myb2x protein, Myb2x-MRE-2r complex, and Myb2x-MRE-2f complex by NMR. The results allow us to pinpoint the molecular mechanism involved in Myb2/DNA interactions.