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At least 127 records · Page 7Linked to original sources
PubMed1988

Gamma endonuclease of Micrococcus luteus: action on irradiated DNA.

Gamma endonuclease is a Mg2+-independent enzyme of Micrococcus luteus that recognizes and cleaves DNA at a variety of altered pyrimidines produced by ionizing radiation. The production of enzyme-recognizable sites (ERS) by ionizing radiation under different irradiation conditions was measured. Ionizing radiation produced the greatest number of ERS when irradiations were performed under anoxic conditions in the presence of the free radical scavenger KI. Since dihydrothymine is a major pyrimidine lesion produced in DNA during anoxic irradiation, the ability of gamma endonuclease to excise this lesion was assessed. Dihydrothymine was released from DNA irradiated under anoxic conditions in a radiation dose-dependent manner, consistent with gamma endonuclease's known DNA glycosylase activity. Gamma endonuclease was also shown to cleave heavily uv-irradiated DNA. When the sequence specificity of gamma-endonuclease cleavage was studied using uv-irradiated DNA, cleavage was seen specifically at cytosines. The identity of this enzyme-recognizable cytosine photoproduct is not known.

Cobalt Radioisotopes↗
PubMed1987

Selective inhibition by methoxyamine of the apurinic/apyrimidinic endonuclease activity associated with pyrimidine dimer-DNA glycosylases from Micrococcus luteus and bacteriophage T4.

The UV endonucleases [endodeoxyribonuclease (pyrimidine dimer), EC 3.1.25.1] from Micrococcus luteus and bacteriophage T4 possess two catalytic activities specific for the site of cyclobutane pyrimidine dimers in UV-irradiated DNA: a DNA glycosylase that cleaves the 5'-glycosyl bond of the dimerized pyrimidines and an apurinic/apyrimidinic (AP) endonuclease that thereupon incises the phosphodiester bond 3' to the resulting apyrimidinic site. We have explored the potential use of methoxyamine, a chemical that reacts at neutral pH with AP sites in DNA, as a selective inhibitor of the AP endonuclease activities residing in the M. luteus and T4 enzymes. The presence of 50 mM methoxyamine during incubation of UV- (4 kJ/m2, 254 nm) treated, [3H]thymine-labeled poly(dA).poly(dT) with either enzyme preparation was found to protect completely the irradiated copolymer from endonucleolytic attack at dimer sites, as assayed by yield of acid-soluble radioactivity. In contrast, the dimer-DNA glycosylase activity of each enzyme remained fully functional, as monitored retrospectively by release of free thymine after either photochemical- (5 kJ/m2, 254 nm) or photoenzymic- (Escherichia coli photolyase plus visible light) induced reversal of pyrimidine dimers in the UV-damaged substrate. Our data demonstrate that the inhibition of the strand-incision reaction arises because of chemical modification of the AP sites and is not due to inactivation of the enzyme by methoxyamine. Our results, combined with earlier findings for 5'-acting AP endonucleases, strongly suggest that methoxyamine is a highly specific inhibitor of virtually all AP endonucleases, irrespective of their modes of action, and may therefore prove useful in a wide variety of DNA repair studies.

DNA Glycosylases↗
PubMed1978

Effects of chloramphenicol on the postreplication repair and sister recombinational DNA exchanges in ultraviolet-irradiated Micrococcus luteus.

The filling of about one third of postreplication DNA gaps in u.v.-irradiated Micrococcus luteus ATCC 4698 is blocked by chloramphenicol (CA) added just before irradiation. Addition of CA 15 min after u.v.-irradiation does not prevent the complete repair of the gaps. U.v.-sensitive M. luteus mutants (ML 6 and ML 15) are identified as defective in different steps of inducible postreplication DNA repair (PRR). PRR in unexcising M. luteus strain G7 is accompanied by the transfer of about 20% of pyrimidine dimers from parental to daughter DNA strands, which indicates the existance of recombinational pathway of PRR. Recombinational PRR in M. luteus is not inhibited by CA.

Chloramphenicol↗
PubMed1993

Dormancy in Stationary-Phase Cultures of Micrococcus luteus: Flow Cytometric Analysis of Starvation and Resuscitation.

Cultures of the copiotrophic bacterium Micrococcus luteus were stored in spent growth medium for an extended period of time following batch culture. After an initial decrease, the total cell counts remained constant at approximately 60 to 70% of the counts at the beginning of storage. The level of viability, as judged by plate counts, decreased to less than 0.05%, while respiration and the ability to accumulate the lipophilic cation rhodamine 123 decreased to undetectable levels. However, using penicillin pretreatment (to remove viable cells) and flow cytometry and by monitoring both the total and viable counts, we found that at least 50% of the cells in populations of 75-day-old cultures were not dead but were dormant. Resuscitation in liquid medium was accompanied by the appearance of a population of larger cells, which could accumulate rhodamine 123 and reduce the dye 5-cyano-2,3-ditolyl tetrazolium chloride to a fluorescent formazan, while a similar fraction of the population was converted to colony-forming, viable cells. We surmise that dormancy may be far more common than death in starving microbial cultures.

Journal Article↗
PubMed1997

Biosynthesis of teichuronic acid in the bacterial cell wall. Purification and characterization of the glucosyltransferase of Micrococcus luteus.

This report describes what is, to our knowledge, the first purification to near homogeneity of an enzyme involved in the biosynthesis of the teichuronic acid of Micrococcus luteus cell walls. The glucosyltransferase of M. luteus, which participates in the biosynthesis of teichuronic acid, was solubilized from cytoplasmic membrane fragments by extraction with buffer solutions containing the detergents Thesit (dodecyl alcohol polyoxyethylene ether; 1 mg/ml) and 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (0.5 mg/ml). The detergent-solubilized enzyme was purified 150-fold, with a recovery of 13% by adsorbent column chromatography, ion-exchange chromatography, gel filtration, and preparative nondenaturing gradient polyacrylamide gel electrophoresis. On the basis of its mobility on native gradient gel, the glucosyltransferase was estimated to have a molecular mass of 440 kDa. The purified native enzyme was a multisubunit protein consisting of subunits of two sizes; their molecular masses were determined to be 52.5 and 54 kDa, respectively, by observation of the mobility of the protein bands in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point of the enzyme was approximately 5.

Anti-Bacterial Agents↗
PubMed1991

Novel anticodon composition of transfer RNAs in Micrococcus luteus, a bacterium with a high genomic G + C content. Correlation with codon usage.

The number and relative amount of isoacceptor tRNAs for each amino acid in Micrococcus luteus, a Gram-positive bacterium with high genomic G + C content, have been determined by sequencing their anticodon loop and its adjacent regions and by selective labelling of tRNAs. Thirty-one tRNA species with 29 different anticodon sequences have been detected. All the tRNAs have G or C at the anticodon first position except for tRNA(ICGArg) and tRNA(NGASer), in response to the abundant usage of NNC and NNG codons. No tRNA with the anticodon UNN capable of translating codon NNA has been detected, in accordance with a very low or zero usage of NNA codons. The relative amount of isoacceptor tRNAs for an amino acid determined by selective labelling strongly correlates with usage of the corresponding codons. On the basis of these and other observations in this and other eubacterial species, we conclude that the relative amount and anticodon composition of isoacceptor tRNA species are flexible, and their changes are mainly adaptive phenomena that have been primarily affected by codon usage, which in turn is affected by directional mutation pressure.

Anticodon↗
PubMed1981

New restriction endonucleases from Flavobacterium okeanokoites (FokI) and Micrococcus luteus (MluI).

Two new restriction endonucleases have been isolated from Flavobacterium okeanokoites IFO12536 and Micrococcus luteus IFO12992 and named FokI and MluI, respectively. Based on analysis of the sequences around the restriction sites, the recognition sequences and cleavage sites of these endonucleases were deduced as below: FokI: (formula: see text). MluI introduces double-strand cleavages at unique sequences that are completely two-fold rotationally symmetric like most type II restriction endonucleases. FokI belongs to a class of restriction endonucleases that recognize specific but asymmetric nucleotide sequences and introduce staggered cleavages at appointed positions away from the recognition sequences.

Bacterial Proteins↗
PubMed1979

Interactions between bacterial membranes and peptidolipids: lysis of micrococcus luteus protoplasts by derivatives of peptidolipidic antibiotics from bacillus subtilis.

The lysis of protoplasts of Micrococcus luteus has been tested with various derivatives of three peptidolipidic antibiotics: iturin A, mycosubtilin and bacillomycin L. The lytic activity is dependent to the nature of the substituting group and to the position of the substituted aminoacid residue. The acetylation of OH groups leads to a decrease of the lytic activity of the natural antibiotics. The methylation of aspartyl residues of bacillomycin L gives a strong lytic activity while natural bacillomycin L has no lytic activity. The methylation of the tyrosyl residue enhances the lytic activities of iturin A and of bacillomycin L-dimethyl ester and reduces that of mycosubtilin. Correlations between the structures of derivatives and their lytic action on M. luteus protoplasts are discussed.

Anti-Bacterial Agents↗
PubMed1982

Enzymatic repair of pyrimidine dimer-containing DNA. A 5' dimer DNA glycosylase: 3'-apyrimidinic endonuclease mechanism from Micrococcus luteus.

A pyrimidine dimer-DNA glycosylase has been purified 20,000-fold from Micrococcus luteus. The enzyme is a single polypeptide chain with Mr = 18,000 that acts specifically on pyrimidine dimers, preferring those in double-stranded DNA to those in single-stranded DNA. The glycosylase cleaves the 5' residue of a pyrimidine dimer generating an apyrimidinic site and a mixed pyrimidine/pyrimidine nucleotide dimer. Under conditions of substrate excess, dimers containing a 5'-thymine are preferred to those with a 5'-cytosine residue. The glycosylase has an associated apyrimidinic/apurinic (AP) endonuclease that prefers apyrimidinic sites at the site of glycosylase action to either apurinic or apyrimidinic residues. This endonuclease is a Class I AP endonuclease in that it cleaves 3' to the AP site generating a 3'-deoxyribose moiety and a 5'-phosphate.

DNA Glycosylases↗
PubMed1994

ATP synthesis and hydrolysis of the ATP-synthase from Micrococcus luteus regulated by an inhibitor subunit and membrane energization.

After incubation for 70 min in Tris-HCl (pH 8.0), the rate of ATP hydrolysis of free and reconstituted ATP-synthase from Micrococcus luteus multiplied about three times. The apparent increase in activity is due to the reversible dissociation of the delta-subunit. Results of experiments on the temperature dependence of the ATP hydrolysis rate of substrate saturated ATP-synthase exhibited a discontinuity in the Arrhenius plot at 32 +/- 0.5 degrees C for the delta-subunit associated enzyme. Below 32 +/- 0.5 degrees C the activation energy, Ea, was 231.5 +/- 5 kJ mol-1, while above this temperature-level it decreased to 76.4 +/- 3 kJ mol-1. ATP synthesis and hydrolysis of the ATP-synthase, co-reconstituted with monomeric bacteriorhodopsin (Halobacterium halobium), showed a lag of 50 s upon the illumination with green light (505-575 nm). This retardation and the activity depended on the ATP-synthase concentration, being typical of the dissociation of an inhibitor protein. The N-terminal protein sequences of the delta- and epsilon-subunit of the ATP-synthase were identified by automated Edman degradation. Alignment of the amino acid sequence and secondary structure calculations for the delta-subunit did not reveal homology to other known ATP-synthase delta-subunits, but significant equivalence to the epsilon-subunit of E. coli. Sequence analysis of the epsilon-subunit from M. luteus showed homology to equivalent regions in delta-subunits and Oligomycin Sensitivity Conferring Protein (OSCP) of other organisms.

Adenosine Triphosphate↗
PubMed2003

Studies on the genomic heterogeneity of Micrococcus luteus strains by macro-restriction analysis using pulsed-field gel electrophoresis.

Macro-restriction analysis by means of double digestion using DraI and VspI demonstrated that they cleaved the genomic DNAs from Micrococcus luteus JCM1464(T), JCM3347, and JCM3348 into four to five fragments in a distinguishable manner by pulsed-field gel electrophoresis (PFGE). Separate digestion with DraI and VspI cleaved the genomic DNA from M. luteus ATCC9341 into a relatively limited number of restriction fragments (six pieces). SspI and XbaI cleaved the genomic DNA from each of the four strains into restriction fragments in a distinctly different and distinguishable manner.Thus, PFGE profiles after digestion with these four restriction enzymes that recognize six specific base sequences demonstrated the heterogeneity at the whole genomic DNA level among the four strains of M. luteus. The size of the genomic DNA of M. luteus ATCC9341 was estimated to be approximately 2.3 Mb by the summing the lengths of the restriction fragments generated by each three restriction enzymes (DraI, SspI, and VspI) and averaging the results.

Base Sequence↗
PubMed1987

Organization and codon usage of the streptomycin operon in Micrococcus luteus, a bacterium with a high genomic G + C content.

The DNA sequence of the Micrococcus luteus str operon, which includes genes for ribosomal proteins S12 (str or rpsL) and S7 (rpsG) and elongation factors (EF) G (fus) and Tu (tuf), has been determined and compared with the corresponding sequence of Escherichia coli to estimate the effect of high genomic G + C content (74%) of M. luteus on the codon usage pattern. The gene organization in this operon and the deduced amino acid sequence of each corresponding protein are well conserved between the two species. The mean G + C content of the M. luteus str operon is 67%, which is much higher than that of E. coli (51%). The codon usage pattern of M. luteus is very different from that of E. coli and extremely biased to the use of G and C in silent positions. About 95% (1,309 of 1,382) of codons have G or C at the third position. Codon GUG is used for initiation of S12, EF-G, and EF-Tu, and AUG is used only in S7, whereas GUG initiates only one of the EF-Tu's in E. coli. UGA is the predominant termination codon in M. luteus, in contrast to UAA in E. coli.

Amino Acid Sequence↗
PubMed1989

Spectinomycin operon of Micrococcus luteus: evolutionary implications of organization and novel codon usage.

The complete DNA sequence of the Micrococcus luteus spectinomycin (spc) operon and its adjacent regions has been determined. The sequence has revealed the presence of genes that are homologous to those of the Escherichia coli ribosomal and related proteins, L14, L24, L5, S8, L6, L18, S5, L30, L15, and secretion protein Y (sec Y), and the gene for adenylate kinase (adk). The gene arrangement in the spc operon is essentially the same as that of E. coli except for the absence in the M. luteus spc operon of the genes for S14 and X protein that exist in the E. coli spc operon. SecY and adk seem to be composed of another operon (adk operon) with at least an open reading frame. The deduced amino acid sequences for these ribosomal proteins are well conserved among the two species (40-65% identity). Reflecting the high genomic guanine and cytosine (GC) content of M. luteus (74%), the codon usage of the genes is extremely biased toward use of G and C, about 94% of the codon third positions being G or C. Seven codons, AUA, AAA, AGA, UUA, GUA, CUA, and CAA, all of which have A at the codon third positions, are completely absent in the M. luteus genes examined. Out of 11 genes in the M. luteus spc and adk operons, 5 (10) use GUG (UGA) and 6 (1) use AUG (UAA) as an initiation (termination) codon.

Amino Acid Sequence↗
PubMed1984

Synthesis of RNA I by the RNA polymerase from Micrococcus luteus on the Escherichia coli plasmid pBR322.

Incubation of DNA-dependent RNA polymerase from Micrococcus luteus (gram-positive) with the plasmid pBR322 under transcription conditions in vitro leads to the formation of a rather short-chained RNA. This transcript is initiated at the same site on pBR322 as RNA I, a defined Escherichia coli RNA polymerase product. M. luteus RNA polymerase initiates transcription at the RNA I site much more efficiently than the E. coli enzyme, using either a plasmid preparation of pBR322 or an appropriate linear restriction fragment as template. In the latter case, cleavage of the restriction fragment 24 or 71 nucleotides (but not 91 nucleotides) upstream of the initiation site destroys template activity. By sequence analysis it was determined that the 3' terminus of the M. luteus RNA polymerase transcription product is identical with that known for RNA I. Moreover, in agreement with synthesis of RNA I by E. coli RNA polymerase in vitro, termination by the M. luteus enzyme is also a stutter process characterized by the same dependence on the available UTP concentration. These observations lead to the hypothesis that termination by eubacterial RNA polymerases might not be species-specific.

Base Sequence↗
PubMed2003

Mutational analysis of allylic substrate binding site of Micrococcus luteus B-P 26 undecaprenyl diphosphate synthase.

Undecaprenyl diphosphate (UPP) synthase catalyzes the sequential cis-condensation of isopentenyl diphosphate (IPP) onto (E,E)-farnesyl diphosphate (FPP). In our previous reports on the Micrococcus luteus B-P 26 UPP synthase, we have shown that the conserved residues in the disordered region from Ser-74 to Val-85 is crucial for the binding of FPP and the catalytic function [Fujikura, K., et al. (2000) J. Biochem. (Tokyo) 128, 917-922] and the existence of a structural P-loop motif for the FPP binding site [Fujihashi, M., et al. (2001) Proc. Natl. Acad. Sci. U.S.A., 98, 4337-4342]. To elucidate the allylic substrate binding site in more detail, we prepared eight mutant enzymes and examined their kinetic behavior. The mutant with respect to the two complementarily conserved Arg residues among the structural P-loop motif, G32R-R42G, retained the activity and showed product distribution pattern exactly similar to that of the wild-type, indicating that the complementarily conserved Arg is important for maintaining the catalytic function. Substitutions of Asp-29, Arg-33, or Arg-80 with Ala resulted in a large loss of enzyme activity, suggesting that these residues are essential for catalytic function. However, the K(m) values of these mutant enzymes for Z-GGPP, which is the first intermediate during the enzymatic cis-condensations of IPP onto FPP, were only moderately different or little changed from those of the wild type. These results suggest that the binding site for the intermediate Z-GGPP having a cis double bond is different to that for the intrinsic allylic substrate, FPP, whose diphosphate moiety is recognized by the structural P-loop.

Alkyl and Aryl Transferases↗
PubMed1984

Metabolism of pyrimidine bases and nucleosides in the coryneform bacteria Brevibacterium ammoniagenes and Micrococcus luteus.

The metabolism of exogenous pyrimidine bases and nucleosides was investigated in Brevibacterium ammoniagenes and Micrococcus luteus with fluorinated analogs and radioactive precursors. Salvage of thymine and thymidine was found in M. luteus, but not in B. ammoniagenes. Exogenous uracil or uracil nucleosides, but not cytosine or cytosine nucleosides, were nucleic acid precursors for both bacteria. By examining the possible nucleoside-metabolizing enzymes, it can be suggested that the pyrimidine salvage pathways in the coryneform bacteria are different from those of members of the family Enterobacteriaceae.

Brevibacterium↗
PubMed1982

[Optimization of lysozyme determination: comparative study of preparations of test cultures of Micrococcus luteus (M. lysodeikticus Fleming)].

About 6000 single measurements of the susceptibility of different preparations of Micrococcus luteus (M. lysodeikticus Fleming) cells were performed in order to assess their suitability for the determination of various muramidase concentrations. In particular, a turbidimetric method was compared with an agar-diffusion technique under varying experimental conditions. From our results it can be concluded that M. luteus cells washed with ether and acetone or living lyophilized cells are most suitable for turbidimetric determinations of lysozyme activity. The optimum conditions for turbidimetric assays comprised an initial transmission of 20% and a test time of 5 min. For the agar-diffusion technique fresh living or living lyophilized cells were most suitable. For a given incubation time of 3 h an incubation temperature of 50 degrees C yielded the best results.

Acetone↗