PROTEIN CHEMOTAXONOMY OF GENUS DATURA - IDENTICAL AMINO-ACID-SEQUENCEOF FERREDOXIN FROM 2 VARIETIES OF DATURA-STRAMONIUM

The complete amino acid sequence of the respective [2Fe-2S] ferredoxin s from two varieties of Datura stramonium, D. stramonium var. stramoni um and D. stramonium var. tatula, have been determined by automated Ed man degradation of the entire Cm-protein and of the peptides obtained by tryptic digestion and CNBr treatment. The ferredoxins from the two plants exhibited identical amino acid sequences, suggesting a very clo se taxonomic relationship between the two. This result supports the pr oposal by Blakeslee and others that these plants, at first named by Li nnaeus as two distinct species, i.e. D. stramonium L. and D. tatula L. , should be considered two varieties of a single species.