NITRIC OXIDE DISRUPTS DNA BINDING OF THE AtMYB2 TRANSCRIPTION FACTOR

SERPA, V; VERNAL, J.; CASSIA, R.; TERENZI, H.

Salvador, Brasil

Congreso; XXXVI Annual Meeting of the Brazilian Society for Biochemistry and Molecular Biology (SBBq) e 10th IUBMB; 2007

Brazilian Society for Biochemistry and Molecular Biology

. In the studies presented here, we have utilized the DBD of AtMYB2 (for simplicity named AtMYB2), an Arabidopsis thaliana transcriptional activator involved in the ABA (abscicic acid) signal transduction pathway under drought stress in plants. As a model to investigate whether MYB domain could be modulated in vitro by the signaling molecule nitric oxide (NO), we have cloned, expressed and purified the R2R3 domain of MYB2 and performed with the purified protein shift assays using the rd22 gene promoter, one of the targets of AtMYB2.NO-generating agent SNP severely inhibited specific DNA binding of AtMYB2 domain. This inhibition was readily reversible upon treatment with excess DTT. This is the first work reporting that the redox-sensitive cysteine (Cys53) might be responsible for this NO sensitivity. We predict that S-nitrosylation disrupts DNA binding by a structural effect