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Synthesis of hybrid bisnucleoside 5',5"'-P1,P4-tetraphosphates by aminoacyl-tRNA synthetases.

Aminoacyl tRNA synthetases, by means of a back reaction, are able to synthesize certain 5', 5"'-P1, P4-bisnucleoside tetraphosphates of biological importance, such as Ap4A. Here it is shown that HisRS and TrpRS (Bacillus stearothermophilus) and AlaRS (E. coli) also synthesize the hybrid compounds Ap4G, Ap4C, and Ap4U. GlnRS (E. coli) is unable to synthesize any of the above compounds. AlaRS synthesizes Ap4U very poorly, and Ap4C and Ap4G almost as effectively as Ap4A. HisRS and TrpRS synthesize Ap4G, Ap4U and Ap3U quite effectively, and Ap4C very poorly. The fact that hybrid bisnucleoside tetraphosphates can be made by the same enzymes, and at rates comparable to Ap4A, suggests that these compounds may also occur in vivo.

Adenine Nucleotides↗

Mechanism of protein synthesis inhibition during stationary phase in Bacillus stearothermophilus.

The appearance of a protein (association factor I) in ribosomes from Bacillus stearothermophilus at stationary phase of growth is described. Association factor I is present on 30S subunits and 30S-50S ribosomal couples, but not on 50S subunits. This protein is responsible for the low levels of polyphenylalanine synthesis shown by stationary phase ribosomes. Association factor I is able to bind to free 30S-50S ribonsomal couples but not to polysomes, and exerts its effect by inhibiting the initiation step of protein synthesis. Ribonsomes preincubated with association factor I have a decreased ability for polypeptide synthesis directed page mRNA or poly(U).

Bacterial Proteins↗

Transformation of synthetic pyrethroid insecticides by a thermophilic Bacillus sp.

Employing a mineral salts medium containing Tween 80 as the primary carbon source, a strain of Bacillus stearothermophilus was isolated which was able to hydrolyse selected second and third-generation pyrethroids to non-insecticidal products. Of a range of pyrethroid insecticides the trans-isomer of permethrin was the most readily transformed by this microbial isolate, whilst flumethrin was the least. 3-Phenoxybenzoic acid and the respective halovinyl or haloacid moieties were detected as the major hydrolytic products of the pyrethroids. It is believed that 3-phenoxybenzoic acid was formed from 3-phenoxybenzyl alcohol which was not however detected as an intermediate in these systems. 3-Phenoxybenzoic acid was further transformed to 4-hydroxy-3-phenoxybenzoic acid. A potential metabolic pathway has been described.

Benzoates↗

Influence of an S-layer on surface properties of Bacillus stearothermophilus.

Various aspects of surface properties of the S-layer-carrying Bacillus stearothermophilus PV72 and of an S-layer-deficient mutant (strain PV72/T5) have been tested by adsorption assays on solid surfaces, electrostatic interaction chromatography and hydrophobic interaction chromatography. The adsorption assays have shown that cell adhesion of the S-layer-carrying strain was less influenced by environmental changes than it was with the S-layer-deficient mutant. Electrostatic interaction chromatography indicated that both strains have positively and negatively charged groups exposed on the cell surface but the S-layer-carrying strain reveals more positively charged groups than does the S-layer-deficient mutant. Hydrophobic interaction chromatography showed that both strains have a hydrophilic surface but that the hydrophilic properties are more pronounced with the strain lacking an S-layer.

Bacterial Adhesion↗

In vivo transcriptional pattern in the infC operon of Bacillus stearothermophilus.

By Northern blot and primer extension analyses it was shown that in Bacillus stearothermophilus the genes infC, rpmI and rplT constitute a single transcriptional unit; the promoter and the transcriptional start-point used in vivo were identified and the half-life of the transcript (1.2 min) was determined. No indication of multiple initiation sites nor of differential stability of different regions of the transcript was found. The results suggest that Escherichia coli and B. stearothermophilus have a different pattern of transcription around the infC gene cluster and that differential translational efficiency within the infC-rpmI-rplT transcriptional unit accounts for the different levels of IF3, L35 and L20 expression. The rare AUU initiation codon is the only strictly conserved element of the several peculiar transcriptional and translational features found in E. coli infC. Upon changing this codon to AUG, we found a ca. 30-fold increased expression of B. stearothermophilus infC, which is similar to that previously found with E. coli infC (i.e. 40-fold), and provided evidence that regulation of infC expression through its rare AUU initiation codon might be a general phenomenon in bacteria.

Amino Acid Sequence↗

Temperature related alterations in the acidic alanine-rich "A" protein from the 50S ribosomal particle of the extreme halophile, Halobacterium cutirubrum.

50-S ribosomal subunits from the extreme halophilic bacterium, Halobacterium cutirubrum, contain an alanine-rich acidic "A" protein which resembles the L7--L12 multimer (Kaltschmidt and Wittmann, 1970) found in the 50-S ribosomal subunit of Escherichia coli cells. The protein contains 24 mole % alanine and is devoid of histidine, tryptophan and cysteine. Unlike E. coli which has two forms of the "A" protein distinguished solely by the acetylation state of the serine amino terminus. H. cutirubrum 50-S subunits contain only one unsubstituted form of the "A" protein in vivo. However, during purification of ribosomes from cells grown between 25 and 37 degrees C the latter "A" protein undergoes rapid, specific, in vitro enzymatic alteration at its carboxy-terminal end. When the halophile is grown in the temperature range of 40 to 42 degrees C the cleaving enzyme is not active and only one form of the "A" protein is found on the ribosomes.

Alanine↗

High pressure dissociation of lactate dehydrogenase from Bacillus stearothermophilus and reconstitution of the enzyme after denaturation in 6 M guanidine hydrochloride.

Tetrameric lactate dehydrogenase from Bacillus stearothermophilus exhibits unusual stability towards high hydrostatic pressure: In contrast to the mesophilic enzyme, incubation at pressures up to 2.8 kbar does not cause irreversible denaturation. Hybridization under these conditions suggests partial dissociation to the dimer, indicating that reassociation occurs within the dead-time after pressure release (less than 20 s at less than or equal to 40 micrograms/ml, 20 degrees C). Incubation at P less than 2.8 kbar affects neither the native quaternary structure nor the catalytic function of the enzyme. Reconstitution of the unfolded and dissociated subunits after denaturation, e.g., in 6 M guanidine . HC1, is characterized by fast association favouring the native assembled structure. Evidence from spectroscopic measurements shows that reconstitution starts with a fast refolding reaction generating a native-like conformation. The subsequent rate-determining transconformation of the "structured monomers" governs the kinetics of reactivation and reassociation as one single first-order process. Chemical crosslinking with glutaraldehyde proves that the "structured monomers" undergo fast association to form the tetrameric final state of reconstitution, with significant amounts of dimeric intermediates being detectable. The renatured enzyme is indistinguishable from the native enzyme regarding its physicochemical and enzymological properties (e.g., activation by fructose-1,6-bisphosphate, and susceptibility towards proteolytic digestion).

Drug Stability↗

Functional analysis of the Lactococcus lactis usp45 secretion signal in the secretion of a homologous proteinase and a heterologous alpha-amylase.

The ups45 gene encodes the major extracellular protein from Lactococcus lactis. The deduced sequence of the 27 residue leader peptide revealed the tripartite characteristics of a signal peptide. This leader peptide directed the efficient secretion of the homologous proteinase (PrtP) in L. lactis, indicating that the putative signal peptide of PrtP can be replaced by the 27 residue Usp45 leader peptide. In addition, the 27 residue leader peptide could be used to secrete the Bacillus stearothermophilus alpha-amylase, encoded by the amyS gene. Fusion of the usp45 promoter region and various parts of the leader sequence to an amyS gene devoid of its signal sequence, showed that in Escherichia coli the first 19, 20, and 27 residues of the Usp45 leader are able to direct alpha-amylase secretion. In L. lactis the shorter signal peptides did not result in secretion of alpha-amylase, providing experimental evidence for the hypothesis that gram-positive bacteria require a longer signal peptide for secretion than gram-negative organisms.

Amino Acid Sequence↗

Molecular cloning and nucleotide sequence of the glycogen branching enzyme gene (glgB) from Bacillus stearothermophilus and expression in Escherichia coli and Bacillus subtilis.

The structural gene for the Bacillus stearothermophilus glycogen branching enzyme (glgB) was cloned in Escherichia coli. Nucleotide sequence analysis revealed a 1917 nucleotide open reading frame (ORF) encoding a protein with an Mr of 74787 showing extensive similarity to other bacterial branching enzymes, but with a shorter N-terminal region. A second ORF of 951 nucleotides encoding a 36971 Da protein started upstream of the glgB gene. The N-terminus of the ORF2 gene product had similarity to the Alcaligenes eutrophus czcD gene, which is involved in cobalt-zinc-cadmium resistance. The B. stearothermophilus glgB gene was preceded by a sequence with extensive similarity to promoters recognized by Bacillus subtilis RNA polymerase containing sigma factor H (E - sigma H). The glgB promoter was utilized in B. subtilis exclusively in the stationary phase, and only transcribed at low levels in B. subtilis spoOH, indicating that sigma factor H was essential for the expression of the glgB gene in B. subtilis. In an expression vector, the B. stearothermophilus glgB gene directed the synthesis of a thermostable branching enzyme in E. coli as well as in B. subtilis, with optimal branching activity at 53 degrees C.

1,4-alpha-Glucan Branching Enzyme↗

Molecular cloning of a maltose transport gene from Bacillus stearothermophilus and its expression in Escherichia coli K-12.

Genes responsible for maltose utilization from Bacillus stearothermophilus ATCC7953 were cloned in the plasmid vector pBR325 and functionally expressed in Escherichia coli. The 4.2 kb Bacillus DNA insert in clone pAM1750 suppressed the growth defects on maltose caused by mutations in E. coli maltose transport genes (malE, malK or complete malB deletion) but not mutations in genes affecting intracellular maltose metabolism (malA region). Transport studies in E. coli and B. stearothermophilus suggested that pAM1750 codes for a high affinity transport system, probably one of two maltose uptake systems found in B. stearothermophilus ATCC7953. Nucleotide sequence analysis of a 3.6 kb fragment of pAM1750 revealed three open reading frames (ORFs). One of the ORFs, malA, encoded a putative hydrophobic protein with 12 potential transmembrane segments. MalA showed amino acid sequence similarity to proteins in the superfamily containing LacY lactose permease and also some similarity to MalG protein, a member of a binding protein-dependent transport system in E. coli. The products of two other ORFs were not hydrophobic, did not show similarity to other known sequences and were found not to be essential for maltose utilization in transport-defective E. coli mutants. Hence MalA protein was the only protein necessary for maltose transport, but despite giving a detectable but low level of transport function in E. coli, the protein was very poorly expressed and could not be identified.

ATP-Binding Cassette Transporters↗

Kasugamycin resistant mutants of Bacillus stearothermophilus lacking the enzyme for the methylation of two adjacent adenosines in 16S ribosomal RNA.

Several mutants of B. stearothermophilus have been isolated that are resistant to the antibiotic kasugamycin. One of these is shown to lack dimethylation of two adjacent adenosines in the 16S ribosomal RNA. All mutants that were analyzed biochemically lack the enzyme that is able to methylate this site. Ribosomal sensitivity and resistance to kasugamycin in B. stearothermophilus is therefore, like in E. coli, closely connected with dimethylation of the adenosines.

Adenosine↗

Cloning and expression of a thermophilic alpha-amylase gene from Bacillus stearothermophilus in Escherichia coli.

A 6.4 Kb HindIII fragment of Bacillus stearothermophilus DY-5 DNA cloned in Escherichia coli using pBR322 as a vector was shown to direct the synthesis of a thermophilic alpha-amylase. In attempts to reduce the size of the insert, the alpha-amylase gene was shown to be contained in a 3.1 Kb HindIII - BamHI fragment of the donor strain DNA. The alpha-amylase gene was stably maintained and expressed efficiently in E. coli. The enzymic properties of alpha-amylase produced in E. coli closely resembled those of the donor strain alpha-amylase and the temperature range for the maximal activity was from 65 degrees C to 80 degrees C. Nearly 100% of the activity remained after heating at 80 degrees C for 15 min. The alpha-amylase was shown to be accumulated in the periplasmic space. It was purified to a nearly homogenous protein with a molecular weight of 61,000, which was very similar in size to that produced by B. stearothermophilus DY-5.

Cloning, Molecular↗

Location of protein S4 on the small ribosomal subunit of E. coli and B. stearothermophilus with protein- and hapten-specific antibodies.

In spite of considerable effort there is still serious disagreement in the literature about the question of whether epitopes of ribosomal protein S4 are accessible for antibody binding on the intact small ribosomal subunit. We have attempted to resolve this issue using three independent approaches: (i) a re-investigation of the exposure and the location of epitopes of ribosomal protein S4 on the surface of the 30S subunit and 30S core particles of the E. coli ribosome, including rigorous controls of antibody specificity, (ii) a similar investigation of protein S4 from Bacillus stearothermophilus and (iii) the labelling of residue Cys-31 of E. coli S4 with a fluorescein derivative the accessibility of which towards a fluorescein-specific antibody was demonstrated directly by fluorimetry. In each of the three cases the antigen (E. coli S4, B. stearothermophilus S4 or fluorescein) was found to reside on the small lobe.

Antibodies, Bacterial↗

Synthesis and secretion of a heat-stable carboxymethylcellulose from Clostridium thermocellum in Bacillus subtilis and Bacillus stearothermophilus.

The cellulase gene celA of Clostridium thermocellum coding for the thermostable endoglucanase A was transferred from Escherichia coli to Bacillus subtilis 168 and B. stearothermophilus CU21 using plasmids derived from the Bacillus vector pUB110. When the structural part of the gene was joined to a pUB110 promoter the recombinant plasmids (pSE102, pSE105) were stably maintained and expressed carboxymethylcellulose (CMCase) activity. In B. stearothermophilus CU21 (pSE105) the clostridial CMCase was produced over a wide temperature range up to the maximal growth temperature (68 degrees C). In contrast to E. coli, all of the CMCase synthesized in bacilli was released into the culture medium. About 50% of the extracellular protein secreted by B. subtilis 168 (pSE102) carrying the celA gene consisted of endoglucanase A. These findings demonstrate the feasibility of producing cellulolytic enzymes from thermophilic anaerobes in bacilli.

Bacillus subtilis↗

Identification, cloning and sequence of the Streptococcus faecium infB (translational initiation factor IF2) gene.

The structural gene for translational initiation factor IF2 (infB) from Streptococcus faecium was identified by cross-hybridization with DNA probes derived from the corresponding gene of Bacillus stearothermophilus. The entire infB gene (ca. 2.8 kb) was cloned and sequenced. The amino acid sequence deduced from the nucleotide sequence shows that S. faecium initiation factor IF2 (785 amino acids, Mr 86,415) displays extensive homology (ca. 69% and 53%) with the region comprising three-quarters of the molecule from the carboxy-terminus of B. stearothermophilus and Escherichia coli IF2, respectively. The region comprising one-quarter of the molecule from the amino-terminus, on the other hand, does not display any significant homology.

Amino Acid Sequence↗

Thermostability and superhelicity of plasmid DNA in Bacillus stearothermophilus.

The thermostability of the staphylococcal plasmids pC194 and pUB110 and their antibiotic-resistance determinants was examined upon transfer to Bacillus stearothermophilus CU21. Plasmid pGS13, a pUB110 derivative carrying the chloramphenicol acetyltransferase (CAT) gene of pC194, could be maintained up to the maximum growth temperature (68 degrees C) by selection for chloramphenicol resistance. In the absence of selective pressure, pGS13 was lost at temperatures above 60 degrees C. Segregational instability of pGS13 was accompanied by a progressive loss of negative superhelicity at elevated temperatures. Thermostable mutants of pGS13 were isolated by screening for expression of the antibiotic-resistance determinants after growth under non-selective conditions. These mutants were found to contain an insertion of a 1.7 kb DNA sequence derived from the cryptic B. stearothermophilus plasmid pBS02. Increased thermostability correlated with preservation of plasmid superhelicity at elevated temperatures.

DNA Restriction Enzymes↗

Cloning and characterization of a gene cluster from Bacillus stearothermophilus comprising infC, rpmI and rplT.

Using two synthetic deoxyribonucleotide probes encoding segments of the primary structure of initiation factor IF3 from Bacillus stearothermophilus, we identified and cloned a segment of DNA which carries the infC gene. As in Escherichia coli, the infC gene begins with the unusual initiation triplet AUU, and is followed by the structural genes for ribosomal proteins L35 and L20 (rpmI and rplT, respectively).

Amino Acid Sequence↗

Nucleotide sequence of the triose phosphate isomerase gene of Escherichia coli.

We report here the complete nucleotide sequence of the E. coli triose phosphate isomerase gene. The gene encodes a polypeptide of 255 amino acids which is approximately 46% homologous to eukaryotic triose phosphate isomerases, and approximately 38% homologous to the enzyme from a thermophilic bacterium, Bacillus stearothermophilus. The nucleotide sequence is 55% homologous to that of the corresponding gene in the yeast Saccharomyces cerevisiae. To our knowledge, this is the first report of the sequence of a gene coding a glycolytic enzyme from a prokaryotic organism.

Amino Acid Sequence↗