Prochlorococcus marinus strain PCC 9511, a picoplanktonic cyanobacterium, synthesizes the smallest urease

• Published in: Microbiology (Society for General Microbiology) 2000-12, Vol.146 (12), p.3099-3107
• Main Authors: Palinska, Katarzyna A, Jahns, Thomas, Rippka, Rosmarie, Tandeau de Marsac, Nicole
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Bacteriology; Biological and medical sciences; Cloning, Molecular; Cyanobacteria - enzymology; Cyanobacteria - growth & development; Cyanophyta; Electrophoresis, Polyacrylamide Gel; Fundamental and applied biological sciences. Psychology; Immunoblotting; Metabolism. Enzymes; Microbiology; Molecular Sequence Data; Molecular Weight; Prochlorococcus marinus; Protein Structure, Quaternary; Protein Subunits; Sequence Analysis, DNA; Urease - antagonists & inhibitors; Urease - chemistry; Urease - genetics; Urease - isolation & purification; Urease - metabolism; ureDABC gene; ureEFG gene
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/00221287-146-12-3099

Unité de Physiologie Microbienne, Département de Biochimie et Génétique Moléculaire, Institut Pasteur (CNRS, URA 1129), 28 rue du Docteur Roux, 75724 Paris, France 1 Institut für Mikrobiologie, Fachrichtung 13.3, Universität des Saarlandes, D-66041 Saarbrücken, Germany 2 Author for correspondence: Nicole Tandeau de Marsac. Tel: [phone]. Fax: [phone]. e-mail: ntmarsac{at}pasteur.fr The urease from the picoplanktonic oceanic Prochlorococcus marinus sp. strain PCC 9511 was purified 900-fold to a specific activity of 94.6 µmol urea min -1 (mg protein) -1 by heat treatment and liquid chromatography methods. The enzyme, with a molecular mass of 168 kDa as determined by gel filtration, is the smallest urease known to date. Three different subunits with apparent molecular masses of 11 kDa ( or UreA; predicted molecular mass 11 kDa), 13 kDa (ß or UreB; predicted molecular mass 12 kDa) and 63 kDa ( or UreC; predicted molecular mass 62 kDa) were detected in the native enzyme, suggesting a quaternary structure of ( ß ) 2 . The K m of the purified enzyme was determined as being 0·23 mM urea. The urease activity was inhibited by HgCl 2 , acetohydroxamic acid and EDTA but neither by boric acid nor by L-methionine-DL-sulfoximine. Degenerate primers were designed to amplify a conserved region of the ureC gene. The amplification product was then used as a probe to clone a 5·7 kbp fragment of the P. marinus sp. strain PCC 9511 genome. The nucleotide sequence of this DNA fragment revealed two divergently orientated gene clusters, ureDABC and ureEFG , encoding the urease subunits, UreA, UreB and UreC, and the urease accessory molecules UreD, UreE, UreF and UreG. A putative NtcA-binding site was found upstream from ureEFG , indicating that this gene cluster might be under nitrogen control. Keywords: P. marinus subsp. pastoris , Prochlorales , nitrogen metabolism, biochemical characterization, ure genes The GenBank accession number for the sequence determined in this work is AF242489 . a Present address: Carl von Ossietzky University, ICBM, Geomicrobiology, PO Box 2503, 26111 Oldenburg, Germany.