Structural and functional characterization of HIPTRX and cyclophilin from sweet orange and interaction studies between PthA from Xanthomonas citri and a cysteine protease from Citrus sinensis

• Grant number: 08/09514-9
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: March 01, 2009
• End date: August 31, 2013
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal Investigator: Celso Eduardo Benedetti
• Grantee: Bruna Medéia de Campos
• Host Institution: Centro Nacional de Pesquisa em Energia e Materiais (CNPEM). Ministério da Ciência, Tecnologia e Inovação (Brasil). Campinas , SP, Brazil

Abstract

Xanthomonas citri is the causal agent of citrus canker, a disease characterized by the formation of hyperplastic lesions on the surface of the host epidermis. The molecular mechanism by which X. citri induces pustules formation and eventually rupture of the host epidermis is not entirely clear, however, it has been shown that members of the PthA/AvrBs3 family of effector proteins are required to elicit cankers on citrus. To gain clues into the mode of action of X. citri PthA proteins, a two-hybrid approach was used to identify orange proteins that interact with different PthA variants. The identified proteins are either associated with protein folding and activation or transcriptional control mechanisms, which is consistent with the role of PthA as a transcriptional factor. In this work, we intend to characterize the interaction between PthA and a cysteine protease from sweet orange, though to activate the PthA protein. In addition, we plan to crystallize and solve the structure of cyclophilin and HIPTRX, separately or in complex, since these proteins have been shown to interact to each other and play a role as chaperones required for the folding of effector proteins. (AU)