Poster abstracts

Poster number 3 submitted by Balasubrahmanyam Addepalli

Disulfide linkage in the endonuclease motif of Arabidopsis CPSF30 ortholog

Balasubrahmanyam Addepalli (Chemistry, University of Cincinnati), Patrick A Limbach (Chemistry, University of Cincinnati), Arthur G Hunt (Plant and Soil Sciences, University of Kentucky)

Abstract:
The Arabidopsis ortholog of the 30 kDa subunit of the cleavage and polyadenylation factor (AtCPSF30) is an RNA binding endonuclease, and the endonuclease activity is inhibited by reducing agents. Here, we report the presence of a disulfide linkage in the endonuclease motif. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) was used to compare the reduced and non-reduced protein. This analysis reveals presence of a disulfide bond within the third predicted CCCH -zinc finger, the motif that catalyzes the endonuclease activity of AtCPSF30. This raises the possibility that redox regulation of AtCPSF30 may occur through the disulfide linkage.

References:
1. Delaney, K.J., Xu, R., Zhang, J., Li, Q.Q., Yun, K.Y., Falcone, D.L. and Hunt, A.G. (2006). Calmodulin interacts with and regulates the RNA-binding activity of an Arabidopsis polyadenylation factor subunit. Plant Physiology 140, 1507-1521.

2. Addepalli, B. and Hunt, A.G. (2007). A novel endonuclease activity associated with the Arabidopsis ortholog of the 30-kDa subunit of cleavage and polyadenylation specificity factor. Nucleic Acids Research 35, 4453-4463.

3. Zhang, J., Addepalli, B., Yun, K.Y., Hunt, A.G., Xu, R., Rao, S., Li, Q.Q. and Falcone, D.L. (2008). A polyadenylation factor subunit implicated in regulating oxidative signaling in Arabidopsis thaliana. PLoS ONE 3

4. Addepalli, B. and Hunt, A.G. (2008). Redox and heavy metal effects on the biochemical activities of an Arabidopsis polyadenylation factor subunit. Archives of Biochemistry and Biophysics 473, 88-95.

Keywords: CPSF30, Endonuclease, Disulfide linkage