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PubMed1970

Dinucleotides as products of an exonucleolytic activity association with the Micrococcus luteus DNA polymerase.

The partially purified DNA polymerase from Micrococcus luteus contains a low level of exonucleolytic activity. The enzyme preparation (1200-fold purified) contains approximately 100 times more polymerase than exonuclease activity. Both single- and double-stranded DNA are degraded at the same rate. The predominant products are dinucleoside diphosphates (d-pXpY); mononucleotides and a trace of trinucleotides are also produced. Each of these products is formed at a constant rate throughout the course of the reaction. The nuclease degrades a DNA chain from the 5'-end. The enzyme preparation contains no detectable endonuclease activity.

Carbon Isotopes↗
PubMed1977

The enzymatic conversion of L-histidine to urocanic acid by whole cells of Micrococcus luteus immobilized on carbodiimide activated carboxymethylcellulose.

Whole cells of Micrococcus luteus (formerly Sarcina lutea ATCC 9341) have been covalently linked to a carboxymethylcellulose support system, with the retention of histidine ammonia-lyase activity. The dependence of the rate of urocanic acid formation on pH, temperature, and added surfactant concentration was similar for the free and the immobilized cells. The immobilization procedure used is based on the carbodiimide activation of carboxymethylcellulose and has been optimized for the histidine ammonia-lyase activity of the immobilized cells on a given weight of cellulose. In a column reactor at 23 degrees C and superficial velocity of 0.044 cm/min, 5 g of cellulose with bound cells gave a 35% conversion of an L-histidine solution (0.25M, pH 9.0) to urocanic acid for 16 days of continuous operation. The scope of this carbodiimide assisted immobilization procedure has been investigated for a series of microorganisms and a variety of carboxylate functionalized supports.

Ammonia-Lyases↗
PubMed1997

Purification and properties of an alpha-amylase produced by a cassava-fermenting strain of Micrococcus luteus.

An extracellular alpha-amylase produced by a cassava-fermenting strain of Micrococcus luteus was purified 26-fold by gel filtration and ion-exchange chromatography. The molar mass was estimated to be approximately 56 kDa. The optimum temperature of the enzyme was 30 degrees C, optimum pH 6.0 and optimum substrate concentration was 0.6% (W/V). Treatment of the enzyme at 70 degrees C for 10 min resulted in 70% loss of activity. The activation energy was determined to be 34.8 kJ/mol. The activity of the enzyme was enhanced by Mg2+, Ca2+, K+, Na+ and inhibited by EDTA, KCN and citric acid. The enzyme may find some application in local food processing.

Bacterial Proteins↗
PubMed2025

Adaptive laboratory evolution of Micrococcus luteus and identification of genes associated with radioresistance through genome-wide association study.

Micrococcus luteus (V017) is a Gram-positive bacterium that was isolated from a sterilization area exposed to 60Co radiation. In this study, we performed an adaptive laboratory evolution experiment with M. luteus, exposing it to 24 continuous cycles of gamma irradiation at four different doses (1.5 kGy, 3.5 kGy, 5.5 kGy, and 7.5 kGy). This led to the creation of four evolved populations with different levels of radioresistance, which were positively correlated with the radiation dose applied. The survival rate of the evolved population that underwent adaptive treatment at the highest dose (7.5 kGy) was 0.69% after exposure to 5.5 kGy, which is about five orders of magnitude higher than that of the original strain V017. Furthermore, 76 evolved strains were selected from these populations, and their genomes were re-sequenced, uncovering a total of 3072 mutations. A genome-wide association study identified 56 single nucleotide polymorphisms (SNPs) significantly associated with radioresistance, linked to 62 candidate genes. Ultimately, 9 genes were selected for functional validation. Inactivating 6 of these genes, including H0H31_RS03855 (SMC family ATPase, SbcC), H0H31_RS04250 (ribonuclease HII), H0H31_RS04570 (endonuclease VIII), H0H31_RS07595 (bifunctional 3'-5' exonuclease/DNA polymerase I), H0H31_RS00170 (serine/threonine phosphatase PPP), and H0H31_RS05860 (CBS-domain-containing protein), significantly increased sensitivity to gamma radiation, underscoring their importance in radioresistance.

Micrococcus luteus↗
PubMed1991

Purification of solanesyl-diphosphate synthase from Micrococcus luteus. A new class of prenyltransferase.

The activity of solanesyl-diphosphate synthase from Micrococcus luteus is stimulated by a high molecular mass fraction (HMF) which is separated from cell-free extracts of the same bacterium by DEAE-Toyopearl chromatography followed by Sephadex G-100 chromatography. By employing HMF in the assay procedure, solanesyl-diphosphate synthase was able to be purified to homogeneity and was found to be a homodimer with a monomeric molecular mass of 34 kDa. In contrast to hexaprenyl- and heptaprenyl-diphosphate synthases, which are composed of two easily dissociable components that are inactive unless combined, the homogeneously purified solanesyl-diphosphate synthase itself showed a catalytic activity, though weak, catalyzing the synthesis of both (all-E)-nonaprenyl-(solanesyl-) and (all-E)-octaprenyl diphosphate. HMF does not affect the stability of solanesyl-diphosphate synthase or Km values for isopentenyl diphosphate and farnesyl diphosphate, but it markedly increases Vmax values in a time-dependent manner. Several lines of evidence indicate that HMF contains a factor which binds to polyprenyl products and removes them out of the active site of enzyme to facilitate and maintain the turnover of catalysis.

Alkyl and Aryl Transferases↗
PubMed1975

Postreplication DNA repair in ultraviolet-irradiated Micrococcus luteus.

Postreplication DNA repair was studies in three strains of Micrococcus luteus having different sensitivity to ultraviolet light: a wild type ATCC 5698, a ultraviolet-sensitive mutant G7, deficient in the incision step of repair and in ultraviolet-resistant transformant obtained from G7 by treatment with DNA of wild type cells, Trf(G7). It is shown that the G7 mutant has a low capacity for repair of postreplication DNA gaps compared with the wild type or Trf(G7). It seems to be that postreplication repari capacity contributes significantly to the ultraviolet resistance of M. luteus in addition to the excision repair. In contrast with G7 the size of the DNA fragments synthesized immediately after ultraviolet irradiation in the wild type (and Trf(G7)) seems to be much higher than that expected if each dimer produces one DNA gap in the daughter strand. Since this cannot only be explained by the excision of dimers from parental DNA we have suggested that a rapid repair of postreplication DNA gap occurs in M. luteus.

Centrifugation, Density Gradient↗
PubMed2004

Molecular cloning, overexpression, and purification of Micrococcus luteus K-3-type glutaminase from Aspergillus oryzae RIB40.

We have for the first time found and cloned the cDNA (AoglsA) of Aspergillus oryzae RIB40, which encodes a 49.9-kDa protein sharing 40% homology with the salt-tolerant glutaminase of Micrococcus luteus K-3 (Micrococcus glutaminase). AoglsA was subcloned into a series of expression vectors and expressed in Saccharomyces cerevisiae and Escherichia coli. The gene product, which we named AoGls, showed glutaminase activity and was produced in a cell wall fraction of S. cerevisiae and a soluble protein in E. coli. The highest expression level of 186 U/mg was obtained when the AoglsA was inserted into six bases downstream of the Shine-Dalgarno (SD) sequence of pKK223-3 and expressed in E. coli Rosetta (DE3). AoGls was purified by SuperQ-TOYOPEARL, glutamine affinity chromatography, and Butyl-TOYOPEARL. This is the first report on the overexpression and purification of a M. luteus K-3-type glutaminase cloned from an eucaryote.

Amino Acid Sequence↗
PubMed2006

Partial purification of mannosylphosphorylundecaprenol synthase from Micrococcus luteus: a useful enzyme for the biosynthesis of a variety of mannosylphosphorylpolyisoprenol products.

Membrane fractions from Micrococcus luteus catalyze the transfer of mannose from GDP-mannose to mono- and dimannosyldiacylglycerol, mannosylphosphorylundecaprenol (Man-P-Undec), and a membrane-associated lipomannan. This chapter describes the detergent solubilization, partial purification, and properties of Man-P-Undec synthase. The mobility of the mannosyltransferase activity on sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicates that the enzyme is a polypeptide with a molecular weight of approx 30.7 kDa. Utilizing the broad specificity of the bacterial mannosyltransferase provides a useful approach for the enzymatic synthesis of a wide variety of Man-P-polyisoprenol products.

Chromatography, Agarose↗
PubMed2025

Characterization of Micrococcus luteus Lipidome Containing Novel Lipid Families by Multiple Stage Linear Ion-Trap with High Resolution Mass Spectrometry.

Micrococcus luteus (M. luteus) is a ubiquitous, long-existing Gram-positive bacterium with a distinctive yellow or golden color. It is a model organism for laboratory studies due to its small genome and ease of cultivation. However, only limited knowledge about its constituent lipid structure is known, and its entire lipid profile remains unclear. Here, we applied linear ion trap (LIT) multiple-stage mass spectrometry (MSn) with high resolution for structural characterization of the native lipid extract, along with GC/MS analysis of the acid hydrolysate to reveal the structural details of the entire lipidome, which includes the major phosphatidylglycerol (PG), cardiolipin (CL), phosphatidylinositol (PI), dimannosyl diacylglycerol (DMDG), and minor diacylglycerol (DAG) lipid families. Importantly, we also found two extra lipid families, the new phosphatidyl 1,3-propanediol and the known polyprenyl 1-phosphosate that was not previously reported for M. luteus. We also revealed the unique lipidome simplified by the dominance of branched 15:0-fatty acid substituents (>90% branched 15:0-FA with anteiso-15:0 to iso-15:0 abundance ratio of 4/1), which is in line with the small genome of M. luteus. In addition, the applied LIT MSn mass spectrometry revealed a fragmentation pathway that undergoes internal loss of a glycerol residue specific to DMDG, leading to its structural characterization.

Micrococcus luteus↗
PubMed1983

Inhibition of Micrococcus luteus DNA topoisomerase I by UV photoproducts.

The activity of Micrococcus luteus DNA topoisomerase I on UV-irradiated supercoiled DNA was studied under either processive or distributive reaction conditions. Changes in DNA structure caused by UV irradiation reduce the rate of DNA relaxation at very low concentration of photoproducts. Under processive conditions the inhibition of the topoisomerase I by photoproducts can be quantitated by measuring the amount of substrate left in the replicative form I band. The mode of action of DNA topoisomerase I was affected by the presence of photoproducts in the DNA substrate, although the ability of the enzyme to form a covalent complex with UV-irradiated supercoiled DNA was not changed. The inhibition of topoisomerase I by UV photoproducts has been compared to the effects of single-stranded DNA and UV-irradiated duplex linear DNA on the enzyme, and the results suggest that the inhibition by photoproducts is caused by changes in the conformation of the supercoil. Our findings indicate the possibility that DNA topoisomerase I plays a role in repair.

DNA, Superhelical↗
PubMed1976

Peptidoglycans synthesized by a membrane preparation of Micrococcus luteus.

By incubation of cell-free particulate preparations from Micrococcus luteus with nucleotidic precursors uridine 5'-diphosphate-N-acetylglucosamine and uridine 5'-diphosphate-N-acetylmuramic acid-L-Ala-D-iso-Glu-L-Lys-D-Ala-D-Ala, several types of peptidoglycans were obtained: soluble peptidoglycan, insoluble peptidoglycan bound to the membrane and solubilized by trypsin, and peptidoglycan, which remained insoluble after the action of trypsin. The structure of each type of peptidoglycan was studied by action of lytic enzymes and separation of the fragments on Sephadex. Soluble peptidoglycans consist of a mixture of un-cross-linked polymers of various molecular weights. Trypsin-solubilized peptidoglycans are also a mixture of polymers of various sizes. They contain a preponderance of un-cross-linked material and some bridges with dimer peptides. Insoluble peptidoglycans, after the action of trypsin, contain about 50% of un-cross-linked peptide residues; in the other moiety, peptide units are cross-linked by D-Ala leads to L-Lys and D-Ala leads to L-Ala bonds which characterize the natural peptidoglycan. Therefore, the cell-free particulate preparation possesses the whole enzymatic system necessary for synthesis of cross-linked peptidoglycan.

Amidohydrolases↗
PubMed2002

Plasmid-borne macrolide resistance in Micrococcus luteus.

A plasmid designated pMEC2 which confers resistance to erythromycin, other macrolides, and lincomycin was detected in Micrococcus luteus strain MAW843 isolated from human skin. Curing of this approximately 4.2 kb plasmid from the host organism resulted in erythromycin sensitivity of the strain. Introduction of pMEC2 into a different M. luteus strain conferred erythromycin resistance upon this strain. Macrolide resistance in M. luteus MAW843 was an inducible trait. Induction occurred at subinhibitory erythromycin concentrations of about 0.02-0.05 micro g ml(-1). Erythromycin and oleandomycin were inducers, while spiramycin and tylosin exerted no significant inducer properties. With heterologous expression experiments in Corynebacterium glutamicum, using hybrid plasmid constructs and deletion derivatives thereof, it was possible to narrow down the location of the plasmid-borne erythromycin-resistance determinant to a region of about 1.8 kb of pMEC2. Sequence analysis of the genetic determinant, designated erm(36), identified an ORF putatively encoding a 281-residue protein with similarity to 23S rRNA adenine N(6)-methyltransferases. erm(36) was most related (about 52-54% identity) to erythromycin-resistance proteins found in high-G+C Gram-positive bacteria, including the (opportunistic) pathogenic corynebacteria Corynebacterium jeikeium, C. striatum, C. diphtheriae and Propionibacterium acnes. This is believed to be the first report of a plasmid-borne, inducible antibiotic resistance in micrococci. The possible role of non-pathogenic, saprophytic micrococci bearing antibiotic-resistance genes in the spreading of these determinants is discussed.

Anti-Bacterial Agents↗
PubMed1997

UV endonuclease of Micrococcus luteus, a cyclobutane pyrimidine dimer-DNA glycosylase/abasic lyase: cloning and characterization of the gene.

The gene of Micrococcus luteus UV endonuclease (cyclobutane pyrimidine dimer-DNA glycosylase/ abasic lyase) was cloned and characterized. The cloned gene, whose product had a predicted molecular mass of 17,120 Da, was found to be capable of complementing the Escherichia coli uvrA6 mutation in vivo with respect to resistance to acetonemediated molecular photosensitization, a treatment producing exclusively cyclobutane pyrimidine dimers in DNA. It also generated a nicking activity specific for photosensitization-treated DNA by in vitro transcription/translation. When expressed in E. coli cells, the gene produced a protein structurally identical with UV endonuclease and possessing an activity consistent with cyclobutane pyrimidine dimer-DNA glycosylase/abasic lyase with respect to the effect of inhibitors and the site of the DNA backbone scission. Furthermore, the UV endonuclease-deficient mutant DB7 was shown to regain the enzyme through transformation with the cloned gene. The deduced amino acid sequence of the gene product was at best 27% identical with that of endonuclease V of phage T4, an enzyme strikingly similar to UV endonuclease in molecular and catalytic properties. Despite this marginal overall similarity in amino acid sequence, four of the seven amino acid residues reported to be functionally important in the T4 enzyme were found to be conserved in the M. luteus enzyme. We propose that the gene be called uveA.

Adenosine Triphosphatases↗
PubMed1995

Micrococcus luteus endocarditis: case report and review of the literature.

This paper includes a report on a case of prosthetic valve endocarditis due to Micrococcus luteus and a review of the sixteen cases of endocarditis due to Micrococcus species reported in the literature. The patient was successfully treated with rifampicin combined for two weeks with gentamicin and vancomycin and for another four weeks with teicoplanin. The hospital course was uneventful and no surgery was required.

Aged↗
PubMed1994

Analysis of a complex plasmid insertion in a phototaxis-deficient transformant of Dictyostelium discoideum selected on a Micrococcus luteus lawn.

A novel method for clonal selection of G418-resistant Dictyostelium discoideum transformants on lawns of Micrococcus luteus was developed. The procedure was used to isolate transformants deficient in phototaxis after nontargeted insertion of shuttle vector DNA. Southern blot analysis as well as restriction, T-tracking, and sequencing analysis of plasmids rescued from the genomic DNA of one of the putative phototaxis gene disruptants showed that it contained a complex multicopy insertion of the vector. While insertions of such plasmid vectors might typically be in tandem multicopy format, they can be much more complex, containing, as in this case, inverse as well as tandemly duplicated copies and various deletions.

Animals↗
PubMed1988

Evidence for a Micrococcus luteus gene homologous to uvrB of Escherichia coli.

Restriction fragments of Micrococcus luteus DNA that contained the gene defined by the mutation of an excision repair-deficient mutant, UVsN1, were cloned from both the parental and mutant strains with the Escherichia coli host-vector system. The wild-type fragment was able to reverse the multiple sensitivity of the mutant to ultraviolet, mitomycin C, and 4-nitroquinoline-1-oxide by one-step transformation. Determination of the nucleotide sequences revealed an open reading frame potentially coding for a protein of 709 amino acid residues, within which the mutation was identified as a CG----TA transition causing a change from serine to phenylalanine. The putative product of the open reading frame showed an extensive amino acid sequence homology to the E. coli UvrB protein comprising 673 residues; the homologous region extended over the greater parts of both polypeptides, in which 55% and 17% of the 659 pairs of aligned amino acids were accounted for by conserved residues and conservative substitutions, respectively. This indicates that the gene defined by the UVsN1 mutation represents a homolog of the E. coli uvrB gene, implying the presence in M. luteus of an enzyme complex homologous to the E. coli UvrABC excinuclease.

Amino Acid Sequence↗
PubMed1995

Purification and cloning of Micrococcus luteus ultraviolet endonuclease, an N-glycosylase/abasic lyase that proceeds via an imino enzyme-DNA intermediate.

Although Micrococcus luteus UV endonuclease has been reported to be an 18-kDa enzyme with possible homology to the 16-kDa endonuclease V from bacteriophage T4 (Gordon, L. K., and Haseltine, W. A. (1980) J. Biol. Chem. 255, 12047-12050; Grafstrom, R. H., Park, L., and Grossman, L. (1982) J. Biol. Chem. 257, 13465-13474), this study describes three independent purification schemes in which M. luteus UV damage-specific or pyrimidine dimer-specific nicking activity was associated with two proteins of apparent molecular masses of 31 and 32 kDa. An 18-kDa contaminant copurified with the doublet through many of the chromatographic steps, but it was determined to be a homolog of Escherichia coli ribosomal protein L6. Edman degradation analyses of the active proteins yielded identical NH2-terminal amino acid sequences. The corresponding gene (pdg, pyrimidine dimer glycosylase) was cloned. The protein bears strong sequence similarities to the E. coli repair proteins endonuclease III and MutY. Nonetheless, traditionally purified M. luteus protein acted exclusively on cis-syn thymine dimers; it was unable to cleave site-specific oligonucleotide substrates containing a trans-syn -I, (6-4), or Dewar thymine dimer, a 5,6-dihydrouracil lesion, or an A:G or A:C mismatch. The UV endonuclease incised cis-syn dimer-containing DNA in a dose-dependent manner and exhibited linear kinetics within that dose range. Enzyme activity was inhibited by the presence of NaCN or NaBH4 with NaBH4 additionally being able to trap a covalent enzyme-substrate product. These last findings confirm that the catalytic mechanism of M. luteus UV endonuclease, like those of other glycosylase/AP lyases, involves an imino intermediate.

Amino Acid Sequence↗