ISOLATION, SEQUENCE, AND EXPRESSION IN ESCHERICHIA-COLI OF THE PSEUDOMONAS SP STRAIN ACP GENE ENCODING 1-AMINOCYCLOPROPANE-1-CARBOXYLATE DEAMINASE

Pseudomonas sp. strain ACP is capable of growth on 1-aminocyclopropane-1-carboxylate (ACC) as a nitrogen source owing to induction of the enzyme ACC deaminase and the subsequent conversion of ACC to alpha-ketobutyrate and ammonia (M. Honma, Agric. Biol. Chem. 49:567-571, 1985). The complete amino acid sequence of purified ACC deaminase was determined, and the sequence information was used to clone the ACC deaminase gene from a 6-kb EcoRI fragment of Pseudomonas sp. strain ACP DNA. DNA sequence analysis of an EcoRI-PstI subclone demonstrated an open reading frame (ORF) encoding a polypeptide with a deduced amino acid sequence identical to the protein sequence determined chemically and a predicted molecular mass of 36,674 Da. The ORF also contained an additional 72 bp of upstream sequence not predicted by the amino acid sequence. Escherichia coli minicells containing the 6-kb clone expressed a major polypeptide of the size expected for ACC deaminase which was reactive with ACC deaminase antiserum. Furthermore, a lacZ fusion with the ACC deaminase ORF resulted in the expression of active enzyme in E. coli. ACC is a key intermediate in the biosynthesis of ethylene in plants, and the use of the ACC deaminase gene to manipulate this pathway is discussed.