Biochemical localization of the alkaline phosphatase of Bacillus licheniformis as a function of culture age

Localisation of the cell wall-associated phosphodiesterase PhoD of Bacillus subtilis

The localisation of phosphate-starvation-induced phosphodiesterase PhoD from Bacillus subtilis was studied by analysing processing, release and immunogold labelling of the sections. Although the processing of the pre-protein was extremely slow, the major fraction of PhoD could be detected at the surface of the cell wall. The results indicate that inefficient processing of the translocated pre-protein keeps PhoD in a cell wall-associated location. The uncleaved signal peptide might function as a membrane anchor.

Bacillus licheniformis MC14 alkaline phosphatase I gene with an extended COOH-terminus

Bacterial alkaline phosphatases (APases), except those isolated from Bacillus licheniformis, are approximately 45-kDa proteins while eucaryotic alkaline phosphatases are 60 kDa. To answer the question of whether the apparent 60-kDa alkaline phosphatase from Bacillus licheniformis accurately reflected the size of the protein, the entire gene was analyzed. DNA sequence analysis of the alkaline phosphatase I (APaseI) gene of B. licheniformis MC14 indicated that the gene could code for a 60-kDa protein of 553 amino acids. The deduced protein sequence of APaseI showed about 32% identity to those of B. subtilis APase III and IV and had apparent sequence homologies in the core structure and active sites that are conserved among APases of various sources. The extra carboxy-terminal sequence of APaseI, which made the enzyme bigger than other procaryotic APases, was not homologous to those of eucaryotic APases. The amino acid composition of APaseI was most similar to that of salt-dependent APase among the isozymes of B. licheniformis MC14. Another open reading frame of 261 amino acids was present 142 nucleotide upstream of the APaseI gene and its predicted amino acid sequence showed 68% identity to that of glucose dehydrogenase of B. megaterium.

Factors influencing the activity of cellular alkaline phosphatase during growth and sporulation of Bacillus cereus

Alkaline phosphatase (EC 3.1.3.1) is synthesized in media with a low phosphate concentration (0.37 mM of total and 19 microM of inorganic phosphate, respectively) already during the exponential phase of growth of Bacillus cereus. The enzyme is repressed by higher phosphate concentrations (3.7 mM) during the whole growth period; during sporogenesis the enzyme activity in cells slightly increases even under these conditions. During growth the enzyme is not secreted into the medium, a minor amount being released after cessation of growth. The enzyme activity can be increased by adding Zn2+ ions (10 microM). When during growth without phosphate the pH of the medium decreases below 5.0, the enzyme activity temporarily decreases and growth is slowed down, followed by a subsequent increase of the enzyme activity. In this case the onset of sporulation is also delayed.

Two alkaline phosphatase genes positioned in tandem in Bacillus licheniformis MC14 require different RNA polymerase holoenzymes for transcription

Southern transfer analysis of Bacillus licheniformis MC14 DNA, using as probe a DNA fragment from within the coding region of a previously cloned alkaline phosphatase (APase) gene, revealed a second area of hybridization adjacent to the cloned APase gene. A second APase gene (APase II) was subcloned from the same plasmid clone, pMH8, from which the first APase gene (APase I) had been subcloned. The two genes are arranged in tandem with several hundred base pairs separating them. Immunoblot analysis showed that both code for Mr 60,000 proteins that crossreact with anti-APase. Both proteins enzymatically cleave 5-bromo-4-chloro-3-indolyl phosphate. In vitro transcription showed that APase I and APase II are transcribed in the same direction but that the two genes require different forms of Bacillus RNA polymerase: sigma 55- and sigma 37-containing RNA polymerase holoenzymes, respectively.

Cloning and characterization of the Bacillus licheniformis gene coding for alkaline phosphatase

The structural gene for alkaline phosphatase (orthophosphoric monoester phosphohydrolase; EC 3.1.3.1) of Bacillus licheniformis MC14 was cloned into the Pst1 site of pMK2004 from chromosomal DNA. The gene was cloned on an 8.5-kilobase DNA fragment. A restriction map was developed, and the gene was subcloned on a 4.2-kilobase DNA fragment. The minimum coding region of the gene was localized to a 1.3-kilobase region. Western blot analysis was used to show that the gene coded for a 60,000-molecular-weight protein which cross-reacts with anti-alkaline phosphatase prepared against the salt-extractable membrane alkaline phosphatase of B. licheniformis MC14 .

Membrane-associated alkaline phosphatase from Bacillus licheniformis that requires detergent for solubilization: lactoperoxidase 125I localization and molecular weight determination

When membranes of Bacillus licheniformis MC14 were extracted exhaustively with 1 M magnesium, approximately 80% of the membrane-associated alkaline phosphatase (orthophosphoric-monoester phosphohydrolase [alkaline optimum], E.C. 3.1.3.1) was solubilized. The remaining activity could be extracted with a cationic detergent, hexadecylpyridinium chloride, without loss of enzymatic activity. The detergent-extractable alkaline phosphatase was immunoprecipitable with antibody to the salt-extractable alkaline phosphatase or the secreted alkaline phosphatase, had an approximate molecular weight of 60,000, and was localized 100% on the outer surface of the cytoplasmic membrane.

A soluble alkaline phosphatase from Bacillus licheniformis MC14. Histochemical localization, purification, characterization and comparison with the membrane-associated alkaline phosphatase

Growth conditions affect the quantity and distribution of alkaline phosphatase (orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1) in Bacillus licheniformis MC14. The soluble alkaline phosphatase, which has been found in biochemical localization studies between the cell wall and cell membrane (Glynn, J.A., Schaffel, S.D., McNicholas, J.M. and Hulett, F.M. (1977) J. Bacteriol. 129, 1010-1019), was localized via electron microscope histochemistry in cells cultured under conditions which result in increased quantities of this activity. This soluble alkaline phosphatase was stabilized with 20% glycerol and purified to homogeneity as determined by sodium dodecyl sulfate(SDS)-polyacrylamide gel electrophoresis. The purified enzyme is soluble in dilute buffer. This soluble alkaline phosphatase has been characterized and compared to the membrane-associated alkaline phosphatase from this organism.

Effect of cobalt on synthesis and activation of Bacillus licheniformis alkaline phosphatase

The effect of CO2+ on the synthesis and activation of Bacillus licheniformis MC14 alkaline phosphatase has been shown by the development of a defined minimal salts medium in which this organism produces 35 times more (assayable) alkaline phosphatase than when grown in a low-phosphate complex medium or in the defined medium without cobalt. Stimulation of enzyme activity with cobalt is dependent on a low phosphate concentration in the medium (below 0.075 mM) and continued protein synthesis. Cobalt stimulation resulted in alkaline phosphate production being a major portion of total protein synthesized during late-logarithmic and early-stationary-phase culture growth. Cells cultured in the defined medium minus cobalt, or purified enzyme partially inactivated with a chelating agent, showed a 2.5-fold increase in activity when assayed in the presence of cobalt. Atomic spectral analysis indicated the presence of 3.65 +/- 0.45 g-atoms of cobalt associated with each mole of purified active alkaline phosphatase. A biochemical localization as a function of culture age in this medium showed that alkaline phosphatase was associated with the cytoplasmic membrane and was also found as a soluble enzyme in the periplasmic region and secreted into the growth medium.

Lactoperoxidase-125I localization of salt-extractable alkaline phosphatase on the cytoplasmic membrane of Bacillus licheniformis

Previous histochemical and biochemical localizations of alkaline phosphatase in Bacillus licheniformis MC14 have shown that the membrane-associated form of the enzyme is located on the inner surface of the cytoplasmic membrane, and soluble forms are located in the periplasmic space and in the growth medium. The distribution of salt-extractable alkaline phosphatase on the surfaces of the cytoplasmic membrane of B. licheniformis MC14 was determined by using lactoperoxidase-125I labeling techniques. Cells harvested during rapid alkaline phosphatase production were converted to protoplasts or lysed protoplasts and labeled. Analysis of the data obtained indicated that 30% of the salt-extractable, membrane-associated alkaline phosphatase was located on the outer surface of the cytoplasmic membrane, whereas 70% of the membrane-associated enzyme was localized on the inner surface. Controls for protoplast integrity (release of tritiated thymidine or examination of cytoplasmic proteins for label content) indicated excellent protoplast stability. Controls indicated that chemical labeling was not a factor in the apparent distribution of alkaline phosphatase on the membrane. These results support the previously reported histochemical localization of alkaline phosphatase on the membrane inner surface. The presence of alkaline phosphatase on the membrane outer surface is reasonable, considering the soluble forms of the enzyme found in the periplasmic region and in the culture medium.

Alkaline phosphatase from Bacillus licheniformis. Solubility dependent on magnesium, purification and characterization

The membrane-associated alkaline phosphatase (orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1) from Bacillus licheniformis MC14, a facultative thermophile, was purified to homogeneity in buffer containing 0.2 M Mg2+. The alkaline phosphatase purified in this manner is insoluble upon removal of the magnesium by dialysis. This insoluble alkaline phosphatase has been characterized and compared to the previously purified heat-solubilized enzyme (Hulett-Cowling, F.M. and Campbell, L.L. (1971) Biochemistry 10, 1364--1371).

Purification and characterization of extracellular soluble and membrane-bound insoluble alkaline phosphatases possessing phosphodiesterase activities in Bacillus subtilis

A membrane-bound insoluble alkaline phosphatase (APase) and an extracellular soluble APase were purified, respectively, from a membrane preparation of Bacillus subtilis 6160-BC6, which carries a mutation to produce APase constitutively, and from a culture fluid of a mutant strain. RAN 1, isolated from strain 6160-BC6, which produces an extracellular soluble APase. The two preparations were homogeneous, as judged by sodium dodecyl sulfate discontinuous gel electrophoresis and by gel electrophoreses in the presence of 8 M urea at pH 9.3 and 4.3. RAN 1 APase was crystallized. Both preparations possessed phosphatase and phosphodiesterase activities, and their pH optima were both at 9.5. They were competitively inhibited by phosphate or arsenate and were activated by the addition of Ca2+ but not by Zn2+. The APase and alkaline phosphodiesterase activities seemed to be contained in the same protein molecule. The molecular weight of 6160-BC6 APase was estimated to be 46,000 +/- 1,000, and that of RAN 1 APase was estimated to be 45,000 +/- 1,000. The largest difference between the 6160-BC6 and RAN 1 APase's was in solubility in low-ionic-strength solutions. Present results suggest that each enzyme is composed of a single polypeptide chain and that 6160-BC6 APase aggregates in solutions of low ionic strength.