ANTIFUNGAL ACTIVITY OF RECOMBINANT SNAKIN-1 (StSN1r) PROTEIN INVOLVES MEMBRANE PERMEABILIZATION

MUÑOZ FF, ALMASIA NI, PAGANO MR, HOPP HE, DALEO GR, VAZQUEZ-ROVERE C, GUEVARA MG

Villa Carlos Paz, Córdoba, Argentina

Congreso; XLIV Reunión anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2008

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Snakin1 (SN1) is a cysteine-rich peptide isolated from potato tubers with a MW of 6.922 kDa. Previous reports show that SN1 has antimicrobial activity on fungal and bacterial plant pathogens. In order to analyze in depth the antimicrobial mechanism of action, we have successfully subcloned the SN1 cDNA into pQE70 vector, expressed into M15 cells, induced with 1mM IPTG after 2 h. and purified in Ni-agarose column. Recombinant SN1 (StSN1r) was able to inhibit germination of F. solani spores and growth of hyphae at the same concentrations reported for SN1wt in vitro. When F. solani hyphae and spores were incubated with different concentrations of StSN1r, membrane permeabilization of these structures was observed, as shown by the uptake of the fluorescent dye SYTOX Green. These results show that, as reported for other plants antimicrobial cysteine-rich peptides, cytotoxic activity of StSN1 involves plasma membrane permeabilization.