title: Synthesis of a citrulline-rich cyanophycin by use of Pseudomonas putida ATCC 4359.
abstract: Synthesis of cyanophycin (multi-L-arginyl-poly-L-aspartic acid, CGP) in recombinant organisms is an important option to obtain sufficiently large amounts of this polymer with a designed composition for use as putative precursors for biodegradable technically interesting chemicals. Therefore, derivates of CGP, harbouring a wider range of constituents, are of particular interest. As shown previously, cyanophycin synthetases with wide substrate ranges incorporate other amino acids than arginine. Therefore, using an organism, which produces the required supplement by itself, was the next logical step. Former studies showed that Pseudomonas putida strain ATCC 4359 is able to produce large amounts of L-citrulline from L-arginine. By expressing the cyanophycin synthetase of Synechocystis sp. PCC 6308, synthesis of CGP was observed in P. putida ATCC 4359. Using an optimised medium for cultivation, the strain was able to synthesise insoluble CGP amounting up to 14.7 ± 0.7% (w/w) and soluble CGP amounting up to 28.7 ± 0.8% (w/w) of the cell dry matter, resulting in a total CGP content of the cells of 43.4% (w/w). HPLC analysis of the soluble CGP showed that it was composed of 50.4 ± 1.3 mol % aspartic acid, 32.7 ± 2.8 mol % arginine, 8.7 ± 1.6 mol % citrulline and 8.3 ± 0.4 mol % lysine, whereas the insoluble CGP contained less than 1 mol % of citrulline. Using a mineral salt medium with 1.25 or 2% (w/v) sodium succinate, respectively, plus 23.7 mM L-arginine, the cells synthesised insoluble CGP amounting up to 25% to 29% of the CDM with only a very low citrulline content.
authors: Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität, Münster, Corrensstrasse 3, Münster, Germany.
authors: Lars
authors: L
authors: Wiefel
authors: Anna
authors: A
authors: Bröker
authors: Alexander
authors: A
authors: Steinbüchel
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002956:Citrulline / Q000378:metabolism*; D010453:Peptide Synthases / Q000235:genetics / Q000378:metabolism; D016958:Pseudomonas putida / Q000235:genetics / Q000378:metabolism*; D046939:Synechocystis / Q000201:enzymology
chemical_list: D001426:Bacterial Proteins; C024250:cyanophycin; D002956:Citrulline; D010453:Peptide Synthases; C113257:cyanophycin synthase, bacteria