Biochemical characterization of novel DNA-binding proteins related to plant-pathogen interactions

PAVLOVIC, T.; ALVARES, C.E.; VARGAS, W.A.

Mar del Plata

Congreso; LI Reunion Anual de SAIB; 2015

Sociedad Argentina de Investigación en Bioquimica y Biología Molecular

DNA-binding proteins play crucial roles in genomic organization, cell cycle and gene expression regulation. Genomic surveys in plant-pathogenic fungi identified candidate proteins likely to be targeted to host nuclei. Previous functional characterization showed that CgEP1 defines a novel class of DNA binding proteins transported to the host nucleus, and is essential for stalk rot development in maize plants. In the present study, we expressed and biochemically characterized the recombinant version of CgEP1. Although, in silico studies suggest a molecular weight around 40 kDa, the purified protein was processed into discrete polypeptides that range from 40 to 5 kDa displaying two main forms named: bCgEP1 (40 kDa) and sCgEP1 (5 kDa). This observation suggested that CgEP1 might self-proteolytic activity. Besides, structural characterization of CgEP1 at different pHs with or without DNA reveals that several oligomeric forms of CgEP1 are involved in the different conditions evaluated. To analyze the DNA-CgEP1 interaction, incubations of bCgEP1 and sCgEP1 with DNA in different conditions showed that the interaction is dependent on the number of protein molecules, and that CgEP1 also has the ability to alter DNA structure. These results points to novel mechanisms for protein-DNA interactions and shed some light into the molecular mechanisms underlying plant disease development.