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PubMed1979

Solubility characteristics of Micrococcus lysodeikticus membrane components in detergents and chaotropic salts analyzed by immunoelectrophoresis.

In order to evalute the effectiveness and selectivity of various reagents in the solubilization of bacterial membranes, membranes of Micrococcus lysodeikticus were treated with detergents and chaotropic agents. The composition of the extracts so obtained was analyzed by rocket and two-dimensional immunoelectrophoretic techniques. Recoveery of succinate-, malate-, and reduced nicotinamide adenine dinucleotide- (NADH) dehydrogenases, ATPase, succinylated lipomannan and cytochromes in the extracts was measured. Treatment with a variety of non-denaturing detergents produced extracts that were generally qualitatively uniform although quantitative differences were observed. The degree of extraction of various components was correlated with the hydrophile-lipophile balance. Several chaotropic agents were also evaluated as reagents for membrane solubilization. These agents were less effective in extraction of bulk protein, but produced extracts enriched in some membrane components.

Adenosine Triphosphatases↗
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

Evidence for the incorporation of a fluorescent anthracene fatty acid into the membrane lipids of Micrococcus luteus.

9-(2-Anthryl)-nonanoic acid, a newly synthesized photoactivable molecule, is shown to be incorporated into the membrane lipids of the bacterium Micrococcus luteus, through the regular metabolic pathway. This incorporation, which occurs at the sn-1 position exclusively and without any degradation or elongation of the anthracene fatty acid, is accompanied by an upward shift of the chain length of the other fatty acids.

Anthracenes↗
PubMed1994

Electrodiffusion of ethidium cation into Micrococcus luteus cells.

Ethidium bromide fluorescence increased in the presence of Micrococcus luteus cells; this was shown to be due to the interaction of the ethidium cation (Eth) with intracellular nucleic acids. Eth permeation across the cytoplasmic membrane was the rate-limiting step and obeyed first-order kinetics. Both the rate of influx and the amount of Eth in cells depended on respiration and on ATPase activity under aerobic and anaerobic conditions, respectively. The initial rate of uptake positively correlated with the membrane potential and was a linear function of Eth concentration in the range from 2 microM to 1 mM. The data indicate electrodiffusion of Eth into M. luteus.

Adenosine Triphosphatases↗
PubMed1976

Me2+-(13 S) ATPase from Micrococcus sp. ATCC 398E. The effect of trypsin on the purified enzyme.

By trypsin treatment of highly purified ATPase (EC 3.6.1.3) from Micrococcus sp. ATCC 398E, two enzyme modifications have been obtained. (i) ATPase Ta, which has about the same activity as untreated ATPase. (ii) A protein complex Ti, which lacks ATPase activity, but nevertheless binds ATP as shown by affinity chromatography. Trypsin primarily shortens the alpha-chains of the "native" enzyme to alpha-chains and removes the gamma-subunit, thus yielding ATPase Ta. The formation of the protein complex Ti appears to be due to additional cleavage of one alpha-chain into at least two more fractions.

Adenosine Triphosphatases↗
PubMed1978

The radiation-releasable cell wall nuclease of Micrococcus radiodurans. Purification and properties of the native enzyme.

Micrococcus radiodurans is known to possess a surface nuclease located in a mid-wall layer. Previous work showed that hydroxyl radicals, generated by sublethal doses of ionizing radiation, attack the cell wall and initiate release of the active enzyme into the external medium. The enzyme from unirradiated cells has now been purified to homogeneity by a simple 3-step process. The nuclease is a dimer of molecular weight about 260 000 and exonucleolytically degrades both DNA and RNA to 5'-mononucleotides. Single-stranded DNA is degraded at a rate about 200 times faster than double-stranded DNA. Oligonucleotides bearing a terminal 3'-phosphate are resistant to digestion. Dinucleotides must possess a 5'-terminal phosphate and a free 3'-terminal OH to be hydrolyzed. The enzyme has a pH optimum of about 9.0. A metal ion, possibly Ca2+, appears to be tightly bound to the protein. Removal of this metal with EDTA inactivates the enzyme. Simple readdition of Ca2+ does not restore activity although partial function can be recovered by renaturation from urea in the presence of this ion. The availability of pure enzyme should aid in the detection of radiation induced alterations which may be involved in the mechanism of its release from the cell wall.

Cell Wall↗
PubMed1978

Formation of spirodilactone of 4-(2'-carboxyphenyl)-4,4-dihydroxybutyrate from 2-succinylbenzoate in cell-free extracts of Micrococcus luteus.

The enzyme mediated ATP- and, to a lesser extent, CoASH-dependent synthesis of the spirodilactone of 4-(2'-carboxyphenyl)-4,4-dihydroxybutyrate from 2-succinylbenzoate has been demonstrated in membrane-free extracts of Micrococcus luteus and Escherichia coli. The suggestion is made that the spirodilactone is the product of an aberrant reaction involving a compound that is normally an intermediate in the conversion of 2-succinylbenzoate to 1,4-dihydroxy-2-naphthoate.

Adenosine Triphosphate↗
PubMed1978

The positional specificity of a desaturase in the psychrophilic bacterium Micrococcus cryophilus (ATCC 15174).

The positional specificity of the desaturase activity in the psychrophilic bacterium Micrococcus cryophilus (ATCC 15174) is shown to be delta9. The desaturase is inhibited by sterculic acid. Small amounts of delta8, delta10 and delta11 isomers are present. The implications of these findings for fatty acid metabolism in M. cryophilus are discussed. It is suggested that the temperature-dependent chain length change, known to occur in the phospholipid fatty acids of this bacterium, is not mediated by either a temperature-dependent change in desaturase substrate specificity or the induction of new desaturase enzymes with novel positional specificity. It is concluded that the control by temperature of fatty acid chain length is mediated by either a temperature-dependent change in the products of fatty acid synthetase or a temperature-sensitive palmitate elongase.

Fatty Acid Desaturases↗
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↗
PubMed1976

DNA synthesis and repair in permeable cells of Micrococcus radiodurans.

Cells permeable to deoxyribonucleoside triphosphate were prepared from Micrococcus radiodurans, and DNA synthesis and rejoining of strand scissions induced by gamma-rays were investigated. DNA synthesis was stimulated by ATP at an optimal concentration of 1mM. This reaction requires four deoxyribonucleoside triphosphates and MgCl2. NAD inhibited the reaction, but no rejoining of primer DNA was observed. Even in the presence of NAD, DNA which was synthesized in the unirradiated permeable cells had a peak molecular weight of only 1.3 - 10(6). DNA synthesis was stimulated by irradiation of the permeable cells with gamma-rays, but this stimulatory effect was eliminated by the addition of NAD. Both primer and synthesized DNA in the irradiated permeable cells were rejoined in vitro in the presence of NAD and deoxyribonucleoside triphosphates, while those in the unirradiated permeable cells were not rejoined.

Biological Transport↗
PubMed1977

Separation of DNA-dependent DNA polymerase activities in Micrococcus radiodurans.

DNA polymerase activities in Micrococcus radiodurans were separated into two fractions after purification more than 2000 fold. They differ in pH optimum and residual activities in the absence of a full deoxyribonucleoside triphosphates complement. NAD partly inhibited one of the activities. Both activities were eluted as a single peak on gel filtration and sedimented at the same rate on glycerol gradient centrifugation. Molecular weight 140000 was calculated from Stokes radius and sedimentation constant. Deoxyribonuclease activity was detected on one of the polymerase activities which preferentially degraded double-stranded DNA. Priming activity of nicked DNA was reduced by gamma-irradiation. These results have been related to the possible rolls in repair synthesis in vivo or DNA synthesis in permeable cells of M. radiodurans.

DNA↗
PubMed1978

An exonuclease activity associated with DNA polymerase I of Micrococcus radiodurans.

An exonuclease activity is associated with one of three DNA polymerase in Micrococcus radiodurans. The nuclease activity co-sedimented with its DNA polymerase I of this bacterium on glycerol gradient centrifugation. Both activities show the same optimum pH and heat-inactivation kinetics. This nuclease hydrolyzes preferentially double-stranded DNA in an exonucleolytic manner from both ends of the duplex DNA. The products of hydrolysis are mostly deoxyribonucleoside 5'-monophosphate and no nucleosides are released into the acid-soluble fraction. Di- or other oligonucleotides are also produced but their relative amounts are constant during the time of incubation. The exonuclease activity requires Mg2+ and is inhibited by high concentrations of KCl as is DNA polymerase I of M. radiodurans.

DNA Polymerase I↗
PubMed1980

Micrococcus radiodurans surface exonuclease. Dimer to monomer conversion by ionizing radiation-generated aqueous free radicals.

Micrococcus radiodurans possesses an exonuclease firmly bound to a middle cell wall membrane layer. Aqueous OH. radicals generated chemically or by ionizing radiation cause the immediate release of this enzyme into the surrounding medium. The enzyme is located in a hydrophobic site and can also be released by aqueous n-butanol. When extracted by this solvent it is a non-covalently linker dimer and has a molecular weight of 260 000 as determined by gel filtration. When released by radiation generated OH. radicals, the enzyme initially appears in solution as the dimer but is rapidly split by further aqueous radical attack into two 130 000 molecular weight subunits. Hydroxyl radicals are most effective but reducing radicals are also able to monomerize the enzyme. Only the released dimer enzyme is subject to free radical monomerization. Bound dimer enzyme is not split prior to release. No detectable loss of activity or change in catalytic properties accompanies the free radical cleavage of the enzyme. Both subunits of the dimer enzyme possess a tightly bound metal ion (probably Ca2+) required for activity. The monomer but not the dimer enzyme will bind to an anion exchanger. The monomer is susceptible to loss of its metal ion, and consequent inactivation, when exposed to the exchanger in the absence of Ca2+. Besides providing information on some of the immediate non-lethal effects of ionizing radiation, the behavior of this enzyme system demonstrates a potential cellular mechanism by which internally or externally generated free radicals could be utilized by the cell to control various enzymic reactions.

Butanols↗
PubMed1989

Formation of a stable and catalytically active complex of the two essential components of hexaprenyl diphosphate synthase from Micrococcus luteus B-P 26.

Formation of a stable complex of the two essential components of hexaprenyl diphosphate synthase from Micrococcus luteus B-P 26, which represents the catalytically active state of this enzyme, is observed in the presence of a relatively high concentrations of inorganic pyrophosphate or one of the substrates, isopentenyl diphosphate or farnesyl diphosphate. The apparent molecular mass of the complex is estimated to be about 50 kDa by gel filtration with Superose 12.

Alkyl and Aryl Transferases↗
PubMed1983

Biosynthesis of a D-glucosyl polyisoprenyl diphosphate in particulate preparations of Micrococcus lysodeikticus.

Particulate fractions of Micrococcus lysodeikticus incubated with UDP-D-[14C]glucose incorporated radioactivity into a chloroform - methanol-soluble, low-mol. wt. compound, and into a polymer. The low-mol. wt. compound consisted of a glucolipid that was extremely labile to mild acid hydrolysis with the formation of D-[14C]glucose, and to mild alkali, yielding 14C-labeled alpha-D-glucopyranose 1,2-phosphate and D-glucose 2-phosphate. The labeled glucolipid was eluted from a DEAE-cellulose column at a salt concentration higher than that required by synthetic ficaprenyl (D-glucopyranosyl phosphate), and it migrated more slowly than the latter compound in t.l.c. Formation of the glucolipid was stimulated by exogenous ficaprenyl phosphate, but not by C55-dolichyl phosphate. These results suggest that the [14C]glucolipid has the characteristic properties of a polyisoprenyl glucosyl diphosphate.

Carbon Radioisotopes↗
PubMed1978

Evidence for alteration of the membrane-bound ribosomes in Micrococcus luteus cells exposed to lead.

Micrococcus luteus cell exposed to PB(NO3)2 contained cytosol ribosomal particles and disaggregated membranal ribosomal particles as determined by ultracentirifugation and spectral studies. Approx. 60% of the membrane ribosome fraction from lead exposed cells had a sedimentation value of 8.4S. Cytosol ribosomes from lead exposed cells as well as membranal and cytosol ribosomes from control cells were comparable by their contents of predominantly the 70S type with the 50S and 100S present in relatively small amounts. The lead content of the 8.4S component was more than 200 times higher than the components with higher sedimentation coefficients from lead exposed cells and approc. 650 times more than that of control cell ribosomes. The cells exposed to lead, however, showed no adverse effects from the lead in respect to their growth rates and cellular yields. These results indicate that lead is interacting only at specific sites of the membrane and is inducing events initiated only in strategic cellular regions. These data further substantiate that subtle changes do occur in lead exposed cells that show no obvious effects. It is assumed that these 'minor' alterations are, in toto, biologically significant.

Cytoplasm↗
PubMed1995

Reconstitution of bacteriorhodopsin and ATP synthase from Micrococcus luteus into liposomes of the purified main tetraether lipid from Thermoplasma acidophilum: proton conductance and light-driven ATP synthesis.

The archaebacterium Thermoplasma acidophilum is cultivated at 59 degrees C in a medium containing sulfuric acid of pH 2. The purified bipolar membrane spanning main phospholipid (MPL) of this organism can be used to produce stable liposomes of 100-500 nm in diameter either using a French pressure cell detergent dialysis or sonication. Despite a potassium diffusion potential of 186 mV very low ionic permeability of sonicated MPL liposomes was measured using the potassium binding fluorescent indicator benzofuran isophthalate PBF1, which measures net K+ uptake. The latter also remained very low, in the presence of the K(+) ionophore valinomycin and palmitic acid. Addition of valinomycin and the potent uncoupler carbonylcyanid-p-trifluormehoxyphenyl-hydrazone (FCCP), led to a stimulation in potassium uptake. The rate of proton flux can be calculated from the net K(+) uptake. Under these conditions MPL liposomes are 1-2 orders of magnitude less permeable than egg yolk lecithin vesicles. The difference in proton permeability becomes even more pronounced with increasing temperature, examined using the fluorescent pH indicator pyranine. Purified bacteriorhodopsin from Halobacterium halobium was reconstituted into MPL liposomes in order to study the light-driven proton uptake in 150 mM KCl following addition of valinomycin, gramicidin, FCCP and Triton X-100. The light-driven proton transport into the liposomes was increased 30-fold by addition of valinomycin decreased by gramicidin and FCCP, and abolished by Triton X-100. Co-reconstituted MPL proteoliposomes containing bacteriorhodopsin and ATP synthase from Micrococcus luteus were capable of light-driven ATP synthesis demonstrating the functional coupling of proton transport and nucleotide generation in liposomal MPL membranes.

Adenosine Triphosphate↗
PubMed1990

McrI: a novel class-II restriction endonuclease from Micrococcus cryophilus recognizing 5'-CGRY/CG-3'.

A new class-II restriction endonuclease, McrI, with a novel sequence specificity as isolated from the Gram-positive eubacterium Micrococcus cryophilus. McrI recognizes the palindromic hexanucleotide sequence. [sequence: see text] The novel enzyme in the presence of Mg2(+)-ions cleaves specifically both strands as indicated by the arrows. The staggered cuts generate 3'-protruding ends with single-stranded 5'-RY-3' dinucleotide extensions. The McrI recognition sequence was deduced from mapping data on DNAs of bacteriophages theta X174RF and M13mp18RF characterized by one and four cleavage sites, respectively. The cut positions within both strands of the recognition sequence were determined in sequencing experiments by analyzing hydrolysis of phosphodiester bonds within a polylinker region of M13mp18RF DNA containing an additional McrI recognition site including treatment with T4 DNA polymerase. The novel enzyme may be a useful tool for cloning experiments by completion of the enzymes EclXI (5'-C/GGCCG-3'), NotI (5'-GC/GGCCGC-3'), PvuI (5'-CGAT/CG-3') as well as EaeI (5'-Y/GGCCR-3') and XhoII (5'-Y/GATCR-3') characterized by partly identical sequence specificities.

Base Sequence↗