Protein Damage and Repair Controlling Seed Vigor and Longevity

The formation of abnormal isoaspartyl residues derived from aspartyl or asparaginyl residues is a major source of spontaneous protein misfolding in cells. The repair enzyme protein l -isoaspartyl methyltransferase (PIMT) counteracts such damage by catalyzing the conversion of abnormal isoaspartyl residues to their normal aspartyl forms. Thus, this enzyme contributes to the survival of many organisms, including plants. Analysis of the accumulation of isoaspartyl-containing proteins and its modulation by the PIMT repair pathway, using germination tests, immunodetection, enzymatic assays, and HPLC analysis, gives new insights in understanding controlling mechanisms of seed longevity and vigor.