CLONING AND CHARACTERIZATION OF A CDNA-ENCODING ASPARTATE AMINOTRANSFERASE-P-1 FROM LUPINUS-ANGUSTIFOLIUS ROOT-TIPS

A root tip cDNA library, constructed in the lambda Zap II expression v ector, was immunoscreened with a monoclonal antibody raised against as partate aminotransferase-P-1 from Lupinus angustifolius L. var Uniharv est. One 1452-base pair clone was isolated. The encoded protein sequen ce had high homology to both plant and animal aspartate aminotransfera se sequences. The clone was converted to the phagemid form and express ed in Escherichia coli. The expressed protein was enzymically active a nd could be immuno-complexed with aspartate aminotransferase-P-1-speci fic antibodies. The complete aspartate aminotransferase-P-1 cDNA was c loned into the yeast expression vector pEMBL-yex4 and transformed into Saccharomyces cerevisiae strain BRSCS6, which possesses a mutated asp artate aminotransferase gene (the asp5 mutation). Complementation of t he mutation was achieved using this construct.