Purification and partial sequence analysis of plant annexins

A fractionation procedure for annexins involving Ca2(+)-dependent binding to exogenous phospholipid was applied to tomato suspension culture cells. Two polypeptides (34 kDa and 35.5 kDa) were purified and separated from each other and from contaminant pectic polysaccharide by ion-exchange chromatography. After proteolytic digestion of SDS/PAGE-purified products, N-terminal sequencing of the peptide fragments revealed substantial similarity to sequences of known members of the annexin family characterized from a range of animal tissues. In particular, sequence similarity to the 70-amino acid-residue repeat region found in all annexins sequenced to date was present in both of the plant proteins. The data are discussed within the context of annexin involvement in Ca2(+)-mediated events in higher plants.