Ornithine cyclodeaminase from Ti plasmid C58: DNA sequence, enzyme properties and regulation of activity by arginine

• Published in: European journal of biochemistry Vol. 173; no. 1; pp. 123 - 130
• Main Authors: SANS, Notker, SCHINDLER, Ulrike, SCHRÖDER, Joachim
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 05.04.1988; Blackwell
• Subjects: Amino Acid Sequence; Ammonia-Lyases - genetics; Ammonia-Lyases - isolation & purification; Ammonia-Lyases - metabolism; Arginine - analogs & derivatives; Arginine - genetics; Arginine - pharmacology; Bacterial plant pathogens; Bacteriology; Base Sequence; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; Biotechnology; Escherichia coli - genetics; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation - drug effects; Immune Sera; Metabolism. Enzymes; Microbiology; Mission oriented research; Molecular Sequence Data; Physiology and metabolism; Phytopathology. Animal pests. Plant and forest protection; Plasmids; Recombinant Fusion Proteins - analysis; Recombinant Fusion Proteins - immunology; Rhizobium - genetics; Systematics. Structure, properties and multiplication. Genetics; Ornithine cyclodeaminase; Nucleotide sequence; Antibody; Enzyme; Escherichia coli; Gene organization; Phytopathogen; Gene expression; Genetic transfer; Characterization; Regulation(control); Agrobacterium; Arginine; Gene; Ti Plasmid; Aminoacid; DNA; Bacteria; Catabolism; Rhizobiaceae; Escherichieae; Catalyst activity; Enterobacteriaceae
• ISSN: 0014-2956; 1432-1033
• DOI: 10.1111/j.1432-1033.1988.tb13975.x

Nopaline, an abundant opine in plant cells transformed with nopaline‐type Ti plasmids, is catabolized in Agrobacterium by three Ti‐plasmid‐coded steps via arginine and ornithine to proline. The last enzyme, ornithine cyclodeaminase (OCD), converts ornithine directly into proline with release of ammonia. We describe the DNA sequence of the ocd gene from Ti plasmid C58, antiserum against an OCD fusion protein overexpressed in Escherichia coli, induction and identification of the gene product in Agrobacterium and enzymatic properties of the protein. The DNA sequence suggests a soluble protein with a stretch of some homology with ornithine carbamoyltransferases from other bacteria. OCD activity is subject to substrate inhibition, is stimulated by NAD+ {presumably acting as a catalytic cofactor) and is regulated by l‐arginine which has pronounced effects on the optima for pH and temperature and on the Km, for ornithine. The regulation of OCD activity by l‐arginine is discussed as part of the mechanisms which integrate the pathway of Ti‐plasmid‐coded opine utilization with general metabolism in Agrobacterium.