PURIFICATION, CHARACTERIZATION, AND CDNA CLONING OF PROFILIN FROM PHASEOLUS-VULGARIS

Profilin from common bean (Phaseolus vulgaris L.) was purified to homo geneity by poly-L-Pro affinity chromatography and gel filtration. The hypocotyl and symbiotic root nodule protein was detected as a single i soform with a 14.4-kD molecular mass and an isoelectric point of 5.3. Partial amino acid and DNA sequencing of a full-length cDNA clone conf irmed its identity as profilin. An antibody generated against the puri fied protein binds to a protein with the same molecular mass in leaves and nodules. Immunolocalization of the protein showed a diffuse distr ibution in the cytoplasm of hypocotyls and nodules but enhanced staini ng at the vascular bundles. The strong identity of the sequence among the profilins of birch, maize, and bean suggests that it may play an i mportant role in the signal transduction mechanism of plant cells and plant bacterial symbioses.