A type II toxin-antitoxin system is responsible for the cell death at low temperature in Pseudomonas syringae Lz4W lacking RNase R.

RNase R (encoded by the rnr gene) is a highly processive 3' → 5' exoribonuclease essential for the growth of the psychrotrophic bacterium Pseudomonas syringae Lz4W at low temperature. The cell death of a rnr deletion mutant at low temperature has been previously attributed to processing defects in 16S rRNA, defective ribosomal assembly, and inefficient protein synthesis. We recently showed that RNase R is required to protect P.

Role of DEAD-box RNA helicases in low-temperature adapted growth of Antarctic Lz4W.

RNA metabolism is important as RNA acts as a link between genomic information and functional biomolecules, thereby playing a critical role in cellular response to environment. We investigated the role of DEAD-box RNA helicases in low-temperature adapted growth of , as this group of enzymes play an essential role in modulation of RNA secondary structures. This is the first report on the assessment of all major DEAD-box RNA helicases in any Antarctic bacterium.

Exoribonuclease RNase R protects Antarctic Lz4W from DNA damage and oxidative stress.

Bacterial exoribonucleases play a crucial role in RNA maturation, degradation, quality control, and turnover. In this study, we have uncovered a previously unknown role of 3'-5' exoribonuclease RNase R of Lz4W in DNA damage and oxidative stress response. Here, we show that neither the exoribonuclease function of RNase R nor its association with the RNA degradosome complex is essential for this function.

Functional activity of E. coli RNase R in the Antarctic Pseudomonas syringae Lz4W.

Background: In Antarctic P. syringae RNase R play an essential role in the processing of 16S and 5S rRNA, thereby playing an important role in cold-adapted growth of the bacterium. This study is focused on deciphering the in vivo functional activity of mesophilic exoribonuclease R and its catalytic domain (RNB) in an evolutionary distant psychrophilic bacterium Pseudomonas syringae Lz4W.

DEAD box RNA helicases protect Antarctic Pseudomonas syringae Lz4W against oxidative stress.

DEAD box RNA helicases are involved in important cellular processes like RNA metabolism (Processing and Degradation), ribosome biogenesis and translation. Besides being crucial to the formation of cold adapted degradosomes, RNA helicases have been implicated in structural rearrangement of RNA, implying a role in alleviation of RNA secondary structure stabilization at low temperature. This study depicts the results of experiments on protective role played by DEAD box RNA helicases against nucleic acid damaging agents.

Investigating the Functional Role of Hypothetical Proteins From an Antarctic Bacterium sp. Lz4W: Emphasis on Identifying Proteins Involved in Cold Adaptation.

Exploring the molecular mechanisms behind bacterial adaptation to extreme temperatures has potential biotechnological applications. In the present study, sp. Lz4W, a Gram-negative psychrophilic bacterium adapted to survive in Antarctica, was selected to decipher the molecular mechanism underlying the cold adaptation.

pv. Exoribonuclease R Is Required for Complete Virulence in Rice, Optimal Motility, and Growth Under Stress.

Exoribonuclease R (RNase R) is a 3' hydrolytic exoribonuclease that can degrade structured RNA. Mutation in RNase R affects virulence of certain human pathogenic bacteria. The aim of this study was to determine whether RNase R is necessary for virulence of the phytopathogen that causes bacterial blight in rice, pv.

Biochemical characterization of RecBCD enzyme from an Antarctic Pseudomonas species and identification of its cognate Chi (χ) sequence.

Pseudomonas syringae Lz4W RecBCD enzyme, RecBCDPs, is a trimeric protein complex comprised of RecC, RecB, and RecD subunits. RecBCD enzyme is essential for P. syringae growth at low temperature, and it protects cells from low temperature induced replication arrest.

Backbone and stereospecific (13)C methyl Ile (δ1), Leu and Val side-chain chemical shift assignments of Crc.

Carbon catabolite repression (CCR) allows bacteria to selectively assimilate a preferred compound among a mixture of several potential carbon sources, thus boosting growth and economizing the cost of adaptability to variable nutrients in the environment. The RNA-binding catabolite repression control (Crc) protein acts as a global post-transcriptional regulator of CCR in Pseudomonas species. Crc triggers repression by inhibiting the expression of genes involved in transport and catabolism of non-preferred substrates, thus indirectly favoring assimilation of preferred one.

Replication arrest is a major threat to growth at low temperature in Antarctic Pseudomonas syringae Lz4W.

Chromosomal damage was detected previously in the recBCD mutants of the Antarctic bacterium Pseudomonas syringae Lz4W, which accumulated linear chromosomal DNA leading to cell death and growth inhibition at 4°C. RecBCD protein generally repairs DNA double-strand breaks by RecA-dependent homologous recombination pathway. Here we show that ΔrecA mutant of P.

Draft Genome Sequence of the Antarctic Psychrophilic Bacterium Pseudomonas syringae Strain Lz4W.

The psychrophilic bacterium Pseudomonas syringae strain Lz4W was isolated from soil samples from Antarctica to decipher the mechanisms of low-temperature adaptation. We report here the 4.982-Mb draft genome sequence of P.

rnr gene from the antarctic bacterium Pseudomonas syringae Lz4W, encoding a psychrophilic RNase R.

RNase R is a highly processive, hydrolytic 3'-5' exoribonuclease belonging to the RNB/RNR superfamily which plays significant roles in RNA metabolism in bacteria. The enzyme was observed to be essential for growth of the psychrophilic Antarctic bacterium Pseudomonas syringae Lz4W at a low temperature. We present results here pertaining to the biochemical properties of RNase R and the RNase R-encoding gene (rnr) locus from this bacterium.

All three subunits of RecBCD enzyme are essential for DNA repair and low-temperature growth in the Antarctic Pseudomonas syringae Lz4W.

Background: The recD mutants of the Antarctic Pseudomonas syringae Lz4W are sensitive to DNA-damaging agents and fail to grow at 4 degrees C. Generally, RecD associates with two other proteins (RecB and RecC) to produce RecBCD enzyme, which is involved in homologous recombination and DNA repair in many bacteria, including Escherichia coli. However, RecD is not essential for DNA repair, nor does its deletion cause any growth defects in E.

ATPase activity of RecD is essential for growth of the Antarctic Pseudomonas syringae Lz4W at low temperature.

RecD is essential for growth at low temperature in the Antarctic psychrotrophic bacterium Pseudomonas syringae Lz4W. To examine the essential nature of its activity, we analyzed wild-type and mutant RecD proteins with substitutions of important residues in each of the seven conserved helicase motifs. The wild-type RecD displayed DNA-dependent ATPase and helicase activity in vitro, with the ability to unwind short DNA duplexes containing only 5' overhangs or forked ends.

Auxotrophy in natural isolate: minimal requirements for growth of the Antarctic psychrotrophic bacterium Pseudomonas syringae Lz4W.

A chemically defined minimal medium has been developed for growing the Antarctic psychrotrophic bacterium Pseudomonas syringae Lz4W, a model system for studying cold adaptation. This natural isolate from Antarctica has an absolute requirement for two branched chain amino acids, isoleucine and valine, in addition to low osmolality of the growth medium. The bacterium contains threonine deaminase but lacks acetohydroxyacid synthase suggesting that a defect lies in the isoleucine and valine biosynthetic pathway causing auxotrophy.

Exoribonuclease R in Pseudomonas syringae is essential for growth at low temperature and plays a novel role in the 3' end processing of 16 and 5 S ribosomal RNA.

The (3'-->5') exoribonuclease RNase R interacts with the endoribonuclease RNase E in the degradosome of the cold-adapted bacterium Pseudomonas syringae Lz4W. We now present evidence that the RNase R is essential for growth of the organism at low temperature (4 degrees C). Mutants of P.

RecD plays an essential function during growth at low temperature in the antarctic bacterium Pseudomonas syringae Lz4W.

The Antarctic psychrotrophic bacterium Pseudomonas syringae Lz4W has been used as a model system to identify genes that are required for growth at low temperature. Transposon mutagenesis was carried out to isolate mutant(s) of the bacterium that are defective for growth at 4 degrees but normal at 22 degrees . In one such cold-sensitive mutant (CS1), the transposon-disrupted gene was identified to be a homolog of the recD gene of several bacteria.

Exoribonuclease R interacts with endoribonuclease E and an RNA helicase in the psychrotrophic bacterium Pseudomonas syringae Lz4W.

Endoribonuclease E, a key enzyme involved in RNA decay and processing in bacteria, organizes a protein complex called degradosome. In Escherichia coli, Rhodobacter capsulatus, and Streptomyces coelicolor, RNase E interacts with the phosphate-dependent exoribonuclease polynucleotide phosphorylase, DEAD-box helicase(s), and additional factors in an RNA-degrading complex. To characterize the degradosome of the psychrotrophic bacterium Pseudomonas syringae Lz4W, RNase E was enriched by cation exchange chromatography and fractionation in a glycerol density gradient.