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S Isono

Publications and source records attributed to S Isono.

At least 73 records · Page 4Linked to original sources
PubMed1989

Characterization of the gene rimK responsible for the addition of glutamic acid residues to the C-terminus of ribosomal protein S6 in Escherichia coli K12.

Ribosomal protein S6 of wild-type strains of Escherichia coli contains up to six glutamic acid residues at its C-terminus. The first two residues are encoded by the structural gene for this protein (rpsF) and the rest are added post-translationally. Mutants deficient in this modification were isolated and characterized genetically and biochemically. The S6 protein in these mutants appeared to contain only two glutamic acid residues at the C-terminus as expected. The mutated gene was termed rimK and was mapped at 18.7 min between cmlA and aroA. The rimK gene was cloned into a cosmid vector and its nucleotide sequence determined. Analysis of the transcriptional and translational products of this gene indicates that it encodes a protein with an Mr of 31.5 kDa and that it forms an operon with a gene encoding a 24 kDa protein. An rpsF mutant containing a Glu to Lys replacement in the second residue from the C-terminus of protein S6 was isolated. The S6 protein of this mutant was apparently inaccessible to the RimK modification system. This indicates that the RimK modification system requires the wild-type amino acid sequence at least in the C-terminal region of ribosomal protein S6.

Amino Acid Sequence↗
PubMed1989

Cloning and analysis of an Escherichia coli operon containing the rpmF gene for ribosomal protein L32 and the gene for a 30-kilodalton protein.

The chromosomal DNA fragments of Escherichia coli K-12 were cloned into a mini-F cosmid, pRE435, after partial digestion with restriction endonuclease Sau3AI. The clones were first screened for PyrC+ and then for other genes, including rpmF encoding ribosomal protein L32 that had been mapped near pyrC (I. Janda, M. Kitakawa, and K. Isono, Mol. Gen. Genet. 201:443-436, 1985). Thus, we obtained a total of five rpmF-containing clones. The rpmF gene was located on the chromosomal segment in one of the clones (pAY2-5) by insertional mutagenesis with transposon gamma delta, followed by analysis of the gene products by the maxicell method. Hybridization analysis of clone pAY2-5 with the ordered clone bank (Y. Kohara, K. Akiyama, and K. Isono, Cell 50:495-508, 1987) indicates that a gap at the 1,510-kilobase coordinates in the physical map of E. coli can be bridged by this clone. The nucleotide sequence of the region containing rpmF was accordingly established. In addition, the RNA transcripts from the chromosomal region containing rpmF were analyzed, and the transcriptional initiation sites were determined. The results suggest that rpmF forms an operon with the gene termed g30k which codes for a 30-kilodalton protein of unknown function. At least four transcripts were found to code for ribosomal protein L32.

Amino Acid Sequence↗
PubMed1987

Cloning and nucleotide sequencing of the genes rimI and rimJ which encode enzymes acetylating ribosomal proteins S18 and S5 of Escherichia coli K12.

The rimI gene of Escherichia coli K12, which encodes an enzyme catalysing acetylation of the N-terminal alanine of ribosomal protein S18, has been cloned into a mini-F plasmid pRE432 and characterized at the molecular level. Similarly, the rimJ gene, which encodes another acetylating enzyme that is specific for ribosomal protein S5, has been cloned and characterized. From the nucleotide sequence data for the two genes the RimI enzyme was deduced to contain 161 amino acid residues with a calculated molecular weight (Mr) of 18232 and the RimJ enzyme contains 194 amino acid residues with a calculated Mr of 22687. The proteins produced from the two genes in maxi-cells were identified by electrophoresis on acrylamide gels and their operon structure was analysed by insertional mutagenesis with transposon gamma delta (Tn1000) and by measuring the size of their transcripts. Their structural homology was analysed by DNA hybridization and by calculation with computer programs. There is only a low level of overall homology between the two genes except for a 3' terminal region in which a significant degree of homology was noticed.

Acetylation↗
PubMed1986

[Percutaneous transluminal angioplasty in subclavian artery stenosis].

The technique of percutaneous transluminal angioplasty (PTA) that was introduced initially by Dotter and Judkins in 1964 has been applied to various arterial stenoses and some occlusive lesions and has advanced dramatically with the development of the Grüntzig catheter in the treatment of peripheral vascular disease. However, the application to occlusive disease in brachiocephalic arteries is still considered to be disputable and has been made only in selective cases, especially in Japan. We report here a case with stenosis of the left subclavian artery successfully treated with PTA. The patient was 66 year-old man, who had been suffering from transient attacks of vertigo, ataxia, visual disturbance and the left arm claudication. Blood pressure was 150/92 mmHg in the right arm and 110 mmHg in systole in the left arm. Diagnostic arteriography identified the right carotid artery occlusion at its origin and significant stenosis in the proximal left subclavian artery. PTA under fluoroscopic control was performed by passing dilating catheter in antegrade fashion by Seldinger method through the left femoral artery. Anatomic correction was achieved without hemorrhagic or embolic complications. Systolic blood pressure gradient measured at the brachial artery level disappeared immediately after PTA and symptomatic relief was obtained completely. One month later, wide patency of the left subclavian artery and sufficient antegrade flow in the vertebral artery were confirmed angiographically. During follow-up period of 4 months, the patient was asymptomatic. We reviewed the literature reporting PTA for occlusive disease in brachiocephalic arteries and discussed its problems and possibilities, especially for the treatment of subclavian artery stenosis.

Aged↗
PubMed1985

Unstable mutations caused by regional tandem multiplications in the gene for ribosomal protein S4 show thermosensitivity in Escherichia coli.

The nucleotide sequence of the gene rpsD for the ribosomal protein S4 of three thermosensitive mutants of Escherichia coli K12 was determined. It was found that two of them contained regional multiplications of a nucleotide sequence within the gene rpsD. In one case, it is a duplication of a 31 nucleotide stretch and in another it is a triplication of a 41 nucleotide stretch. The thermosensitive phenotype of the two mutants is unstable and reverts at the frequency of approximately 10(-4). The revertants regain the wild-type nucleotide sequence. We postulate that the two mutant genes that contain regional multiplications possibly take an intra-strands secondary structure, which is cleaved to regenerate the wild-type sequence, probably during DNA replication.

Amino Acid Sequence↗
PubMed1985

Cloning and nucleotide sequencing of the genes for ribosomal proteins S9 (rpsI) and L13 (rplM) of Escherichia coli.

The genes for the ribosomal proteins S9 (rpsI) and L13 (rplM) of Escherichia coli have been cloned into a lambda phage vector termed L47.1. The two genes were identified by infecting UV-light irradiated cells with the resultant phages and analyzing the protein products by two-dimensional gel electrophoresis. Suitable DNA fragments of the isolate were cloned subsequently into M13 phage vectors and their nucleotide sequence was determined by the dideoxy method. It is evident that the two genes form a transcriptional unit, the rplM gene being promoter-proximal. There is a typical signal sequence for transcriptional termination after the rpsI gene. The codon usage pattern in the two genes is similar to other ribosomal protein genes of E. coli.

Amino Acid Sequence↗
PubMed1981

Ribosomal protein modification in Escherichia coli. III. Studies of mutants lacking an acetylase activity specific for protein L12.

Among mutants of E. coli selected for temperature-sensitive growth, four were found to possess alterations in ribosomal proteins L7/L12. Of these, three apparently lack protein L7, the acetylated form of protein L12. Genetic analyses have revealed that the mutation responsible for this alteration maps at a locus around 34 min of the current E. coli genetic map, which is clearly different from the location for the structural gene for protein L7/L12 which is situated at 89 min. Hence, the gene affected in these mutants was termed rimL. Tryptic and thermolysin fingerprints of the protein L12 purified from the rimL mutants showed a profile indistinguishable from that of wild-type protein. It was found that the assayed in vitro, in the high-speed supernatant prepared from mutant cells. These results indicated that the three mutants contain mutations in the gene rimL codes for an acetylating enzyme specific for ribosomal protein L12.

Bacterial Proteins↗
PubMed1980

Ribosomal protein modification in Escherichia coli. II. Studies of a mutant lacking the N-terminal acetylation of protein S18.

A mutant of Escherichia coli K12 has been isolated which shows an alteration in the ribosomal protein S18. Genetic analyses have revealed that the mutation causing this alteration maps at 99.3 min of the E. coli genetic map, between dnaC and deo. This indicated that the mutation has occurred in a gene different from the structural gene for this protein which has been located at 94 min. From the N-terminal amino acid sequence analysis it is concluded that the mutation has resulted in loss of the N-terminal acetyl group of this protein. The gene which is affected in this mutant is termed rimI that most likely specifies an enzyme acetylating the N-terminal alanine of protein S18. The mutation does not affect the acetylation of two other ribosomal proteins, S5 and L12, both of which are known to be acetylated in wild-type E. coli K12.

Acetylesterase↗
PubMed1978

Mutations affecting the structural genes and the genes coding for modifying enzymes for ribosomal proteins in Escherichia coli.

Temperature-sensitive mutants of an Escherichia coli K-12 strain PA3092 have been isolated following mutagenesis with nitrosoguanidine, and their ribosomal proteins analyzed by two-dimensional gel electrophoresis. This method was found to be very efficient in obtaining mutants with various structural alterations in ribosomal proteins. Thus a total of some 160 mutants with alterations in 41 different ribosomal proteins have so far been isolated. By characterizing these mutants, we could isolate not only those mutants with alterations in the structural genes for various ribosomal proteins, but also those with impairments in the modification of proteins S5, S18 and L12. Furthermore, a mutant has been obtained which apparently lacks the protein S20 (L26) with a concomitant reduction to a great extent of the polypeptide synthetic activity of the small subunit. The usefulness of these mutants in establishing the genetic architecture of the genes coding for the ribosomal proteins and their modifiers is discussed.

Electrophoresis↗
PubMed1977

Further temperature-sensitive mutants of Escherichia coli with altered ribosomal proteins.

Various alterations in ribosomal proteins were detected in forty-one mutants of E. coli isolated as temperature-sensitive mutants. Out of these, six are new classes of mutants harboring mutations in proteins S3, L5, L7 (L12), L29, L30 and L33. One of them apparently lacks protein L7 of the large subunit. These mutants together with those reported previously (Isono et al., 1976) total one hundred and one ribosomal mutants in thirty different proteins.

Electrophoresis, Agar Gel↗
PubMed1976

Lack of ribosomal protein S1 in Bacillus stearothermophilus.

The 30S ribosomal subunit of Bacillus stearothermophilus migrated as a single band when electrophoresed on agarose-acrylamide composite gels. The addition of the ribosomal protein S1 purified from Escherichia coli resulted in the appearance of an additional band migrating more slowly; 14C-labeled S1 of E. coli was shown to be associated only with this form. Antibody against E. coli protein S1 did not crossreact with either the total 30S ribosomal proteins or the postribosomal supernatant from B. stearothermophilus. These results indicate that B. stearothermophilus lacks a protein equivalent to E. coli S1 and may explain our previous finding [Eur. J. Biochem. 56, 15-22 (1975) that E. coli S1 greatly stimulated the translation by B. stearothermophilus ribosomes of f2 phage RNA.

Bacterial Proteins↗
PubMed1975

Role of ribosomal protein S1 in portein synthesis: effects of its addition to Bacillus stearothermophilus cell-free system.

Products of the f2 phage RNA-directed protein synthesizing systems in vitro, derived from Escherichia coli and Bacillus stearothermophilus, were analyzed. In contrast to other reports, it was found that B. stearothermophilus ribosomes synthesized phage coat protein when the high-speed (100 000 X g) supernatant (S100) and ribosomal wash (crude initiation factors) of homologous origin were used. Furthermore, a marked stimulation of coat protein synthesis was observed with B. stearothermophilus ribosomes when either S100 or ribosomal wash or both from E. coli cells were used instead of the respective homologous components. The principle responsible for this stimulation was identified as the 30-S ribosomal protein S1 present in S100 and ribosomal wash. Purified S1 from E. coli at roughly one-to-one molar ratio to ribosomes resulted in about 10-fold stimulation of the incorporation of [14C]valine when added to the B. stearothermophilus system. This stimulation was observed mainly in the synthesis of coat protein and replicase.

Amino Acids↗
PubMed1975

Purification and characterization of 30-S ribosomal proteins from Bacillus stearothermophilus.

Twenty-three proteins were identified by two-dimensional eletrophoresis on polyacrylamide-gel slabs in the 30-S ribosomal subunit of Bacillus stearothermophilus strain 799. They were designated as B-S1 through B-S21, B-Sa and B-Sb and purified on carboxymethyl-cellulose and Sephadex G100 in the presence of 6 M urea. Their molecular weight was estimated by dodecyl-sulfate-gel electrophoresis and their amino acid composition was determined after acid hydrolysis. Results obtained for the individual proteins were essentially similar to those for Escherichia coli 30-S proteins with some characteristic differences.

Amino Acids↗