| Pathogenesis related 10 (PR-10) proteins have important roles in mediating plant abiotic and biotic stress tolerance. Most of the members of this family possess ribonuclease activity. The homologues of PR-10 (ABR17) protein, MLP423 and Bet v 1, may have similar biological and physiological functions. The deduced amino acid sequence of MLP423 and Bet v 1, when compared to ABR17, indicated several conserved amino acids and a conserved P-loop motif (GxGGxGxxK). In the present investigation, cDNAs encoding Arabidopsis thaliana MLP423 and Bet v 1 were isolated and cloned, recombinant proteins expressed in E. coli, and purified using Ni-NTA and size exclusion chromatography. Both in-solution and in-gel RNase activity assays were conducted to determine whether these recombinant proteins possessed RNase activity, which indicated that neither MLP423 nor Bet v 1 possessed RNase activity. Our results are discussed in the context of the possible functions of these PR-10 homologues in plants. |
