PCM-1 activity measurements in various C. elegans strains.

Nematode protein extracts were prepared from liquid culture and analyzed for PCM-1 methyltransferase activity as described by Kagan et al. (1997). Protein extracts were incubated with the methyl-accepting peptide substrate KASA-isoD-LAKY (100 µM) and 20 µM [14C]-AdoMet at 30°C for 2 h. Control incubations were conducted as above except that KASA-isoD-LAKY was not added to the reaction. Protein L-Isoaspartyl O-methyltransferase activity levels are given as the amount of methyl groups transferred after correction for the background levels measured in the absence of KASA-isoD-LAKY for the various C. elegans strains used in the lifespan analyses, thermotolerance assays, RT-qPCR analyses, and isoaspartyl quantifications performed in this study. The results shown are means (± SD) of two separate activity measurements conducted with one set of lysates.