Expression, purification and crystallization of a septins complex

• Grant number: 11/23302-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2012
• End date: January 31, 2013
• Field of knowledge: Biological Sciences - Biophysics - Molecular Biophysics
• Principal Investigator: Joci Neuby Alves Macedo
• Grantee: João Victor de Souza Cunha
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 98/14138-2 - Center for Structural Molecular Biotechnology, AP.CEPID

Abstract

Septins belong to the GTPase family, which were initially identified in yeast, but that have representatives members in many eukaryotes, except plants. Structurally, septins contain three regions: a variable N-terminal domain rich in proline, a central GTPase domain, and a C-terminal domain predicted as a coiled-coil. Currently, 13 human septins were identified and classified into four groups according to the similarities in the C-terminal domain primary structures. In humans, there is much evidence of septin's importance on cellular processes. Besides, their presence in cytoplasmatic inclusions bodies has been observed, related to neurodegenerative diseases (Parkinson's and Alzheimer's) and some types of cancer. An interesting aspect of the septins, whose mechanism is not yet understood, is that they are capable of polymerizing among them to form hetero-oligomers, resulting in highly organized filaments. In this context, this proposal aims to expand the study of the septins, in an approach directed to the structure of their complexes. The target for the crystallization assays and structural resolution will be the complex formed by septins 5, 6, and 7. This complex was chosen based on previous results about the interaction of septins through a two-hybrid system and for showing only one substitution in the canonic complex of the septins 2, 6, and 7. This research will certainly contribute to the advances in the knowledge of the heterocomplexes of septins and how these proteins interact among themselves in the complex formation. (AU)