title: Lmo0036, an ornithine and putrescine carbamoyltransferase in Listeria monocytogenes, participates in arginine deiminase and agmatine deiminase pathways and mediates acid tolerance.
abstract: Listeria monocytogenes is a foodborne pathogen causing listeriosis. Acid is one of the stresses that foodborne pathogens encounter most frequently. The ability to survive and proliferate in acidic environments is a prerequisite for infection. However, there is limited knowledge about the molecular basis of adaptation of L. monocytogenes to acid. Arginine deiminase (ADI) and agmatine deiminase (AgDI) systems are implicated in bacterial tolerance to acidic environments. Homologues of ADI and AgDI systems have been found in L. monocytogenes lineages I and II strains. Sequence analysis indicated that lmo0036 encodes a putative carbamoyltransferase containing conserved motifs and residues important for substrate binding. Lmo0036 acted as an ornithine carbamoyltransferase and putrescine carbamoyltransferase, representing the first example, to our knowledge, that catalyses reversible ornithine and putrescine carbamoyltransfer reactions. Catabolic ornithine and putrescine carbamoyltransfer reactions constitute the second step of ADI and AgDI pathways. However, the equilibrium of in vitro carbamoyltransfer reactions was overwhelmingly towards the anabolic direction, suggesting that catabolic carbamoyltransferase was probably the limiting step of the pathways. lmo0036 was induced at the transcriptional level when L. monocytogenes was subjected to low-pH stress. Its expression product in Escherichia coli exhibited higher catabolic carbamoyltransfer activities under acidic conditions. Consistently, absence of this enzyme impaired the growth of Listeria under mild acidic conditions (pH 4.8) and reduced its survival in synthetic human gastric fluid (pH 2.5), and corresponded to a loss in ammonia production, indicating that Lmo0036 was responsible for acid tolerance at both sublethal and lethal pH levels. Furthermore, Lmo0036 played a possible role in Listeria virulence.
authors.affiliation: Zhejiang University Institute of Preventive Veterinary Medicine and Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, 388 Yuhangtang Road, Hangzhou, Zhejiang 310058, PR China.
authors.forename: Jianshun
authors.initials: J
authors.lastname: Chen
authors.affiliation: Zhejiang University Institute of Preventive Veterinary Medicine and Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, 388 Yuhangtang Road, Hangzhou, Zhejiang 310058, PR China.
authors.forename: Changyong
authors.initials: C
authors.lastname: Cheng
authors.affiliation: Zhejiang University Institute of Preventive Veterinary Medicine and Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, 388 Yuhangtang Road, Hangzhou, Zhejiang 310058, PR China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Xia
authors.affiliation: Zhejiang University Institute of Preventive Veterinary Medicine and Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, 388 Yuhangtang Road, Hangzhou, Zhejiang 310058, PR China.
authors.forename: Hanxin
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Zhejiang University Institute of Preventive Veterinary Medicine and Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, 388 Yuhangtang Road, Hangzhou, Zhejiang 310058, PR China.
authors.forename: Chun
authors.initials: C
authors.lastname: Fang
authors.affiliation: Zhejiang University Institute of Preventive Veterinary Medicine and Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, 388 Yuhangtang Road, Hangzhou, Zhejiang 310058, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Shan
authors.affiliation: Zhejiang Provincial Center for Disease Control and Prevention, 630 Xincheng Road, Hangzhou, Zhejiang 310051, PR China.
authors.forename: Beibei
authors.initials: B
authors.lastname: Wu
authors.affiliation: Zhejiang University Institute of Preventive Veterinary Medicine and Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, 388 Yuhangtang Road, Hangzhou, Zhejiang 310058, PR China.
authors.forename: Weihuan
authors.initials: W
authors.lastname: Fang
mesh_terms: D000143:Acids / Q000378:metabolism*; D000595:Amino Acid Sequence; D000641:Ammonia / Q000032:analysis; D000818:Animals; D001679:Biogenic Amines / Q000032:analysis; D019878:Carboxyl and Carbamoyl Transferases / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D005816:Genetic Complementation Test; D006863:Hydrogen-Ion Concentration; D006867:Hydrolases / Q000378:metabolism*; D008089:Listeria monocytogenes / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity; D051379:Mice; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D020539:Sequence Analysis, Protein; D014774:Virulence
chemical_list: D000143:Acids; D001679:Biogenic Amines; D004269:DNA, Bacterial; D000641:Ammonia; D019878:Carboxyl and Carbamoyl Transferases; C022487:putrescine carbamoyltransferase; D006867:Hydrolases; C019626:agmatine deiminase; C019723:arginine deiminase