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M Yaguchi

Publications and source records attributed to M Yaguchi.

At least 73 records · Page 4Linked to original sources
PubMed1990

Glutamyl-tRNA synthetases of Bacillus subtilis 168T and of Bacillus stearothermophilus. Cloning and sequencing of the gltX genes and comparison with other aminoacyl-tRNA synthetases.

The glutamyl-tRNA synthetase (GluRS) of Bacillus subtilis 168T aminoacylates with glutamate its homologous tRNA(Glu) and tRNA(Gln) in vivo and Escherichia coli tRNA(1Gln) in vitro (Lapointe, J., Duplain, L., and Proulx, M. (1986) J. Bacteriol. 165, 88-93). The gltX gene encoding this enzyme was cloned and sequenced. It encodes a protein of 483 amino acids with a Mr of 55,671. Alignment of the amino acid sequences of four bacterial GluRSs (from B. subtilis, Bacillus stearothermophilus, E. coli, and Rhizobium meliloti) gives 20% identity and reveals the presence of several short highly conserved motifs in the first two thirds of these proteins. Conserved motifs are found at corresponding positions in several other aminoacyl-tRNA synthetases. The only sequence similarity between the GluRSs of these Bacillus species and the E. coli glutaminyl-tRNA synthetase (GlnRS), which has no counterpart in the E. coli GluRS, is in a segment of 30 amino acids in the last third of these synthetases. In the three-dimensional structure of the E. coli tRNA(Gln).GlnRS.ATP complex, this conserved peptide is near the anticodon of tRNA(Gln) (Rould, M. A., Perona, J. J., Söll, D., and Steitz, T. A. (1989) Science 246, 1135-1142), suggesting that this region is involved in the specific interactions between these enzymes and the anticodon regions of their tRNA substrates.

Amino Acid Sequence↗
PubMed1990

The Glu residue in the conserved Asn-Glu-Pro sequence of two highly divergent endo-beta-1,4-glucanases is essential for enzymatic activity.

We initially aligned 28 different cellulase sequences in pairwise fashion and found half of them have the sequence -Asn-Glu-Pro- located in a region flanked by hydrophobic-rich amino acids. Based on lysozyme as a model, the glutamate residue could be essential for enzyme function. We tested this possibility by site-directed mutagenesis of the genes coding Bacillus polymyxa and Bacillus subtilis endo-beta-1,4-glucanases. The genes and amino acid sequences of these two enzymes show very little similarity. Change of Glu-194 and Glu-169 to the isosteric glutamine form in these respective enzymes resulted in a dramatic loss of CMCase activity which could be restored by reverse mutation. Similar mutations to less-conserved residues, Glu-72 and Glu-147, of the B. subtilis enzyme did not cause any loss of activity.

Amino Acid Sequence↗
PubMed1990

The amino acid sequence of chymopapain from Carica papaya.

Chymopapain is a polypeptide of 218 amino acid residues. It has considerable structural similarity with papain and papaya proteinase omega, including conservation of the catalytic site and of the disulphide bonding. Chymopapain is like papaya proteinase omega in carrying four extra residues between papain positions 168 and 169, but differs from both papaya proteinases in the composition of its S2 subsite, as well as in having a second thiol group, Cys-117. Some evidence for the amino acid sequence of chymopapain has been deposited as Supplementary Publication SUP 50153 (12 pages) at the British Library Document Supply Centre, Boston Spa., Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies may be obtained on the terms indicated in Biochem. J. (1990) 265, 5. The information comprises Supplement Tables 1-4, which contain, in order, amino acid compositions of peptides from tryptic, peptic, CNBr and mild acid cleavages, Supplement Fig. 1, showing re-fractionation of selected peaks from Fig. 2 of the main paper. Supplement Fig. 2, showing cation-exchange chromatography of the earliest-eluted peak of Fig. 3 of the main paper, Supplement Fig. 3, showing reverse-phase h.p.l.c. of the later-eluted peak from Fig. 3 of the main paper, and Supplement Fig. 4, showing the separation of peptides after mild acid hydrolysis of CNBr-cleavage fragment CB3.

Amino Acid Sequence↗
PubMed1989

Purification and characterization of trehalase inhibitor from hemolymph of the American cockroach, Periplaneta americana.

An endogenous proteinaceous inhibitor of trehalase (alpha,alpha-trehalose-1-glucohydrolase: EC 3.2.1.28) has been isolated and purified from the serum of resting adult American cockroaches, Periplaneta americana. Purification procedures involved decreasing ionic strength, gel filtration, and reversed phase high performance liquid chromatography. Homogeneity was confirmed by polyacrylamide gel electrophoresis and end group analysis. The purified protein inhibited trehalase activity in a dose-dependent manner and was estimated to have a molecular weight of 86,000 and to contain sugar chains. An automated gas-phase sequencer was used to determine the following sequence for the N-terminal amino acid residues: H-Ala-Ilu-Pro-Thr-Pro-His-Val-Tyr-Lys-Val-X-Val-Pro-Asp-Gly-Ala-Le u-Asn-Asp.

Amino Acid Sequence↗
PubMed1988

The amino acid sequence of a gonococcal growth inhibitor from Staphylococcus haemolyticus.

A gonococcal inhibitor produced by Staphylococcus haemolyticus was separated into three components by reverse-phase h.p.l.c. The amino acid composition analysis of each of the three components indicated extensive similarities. N-Terminal sequence analysis of all three components allowed the identification of the first 27-30 residues of each. The complete primary structure of each component was determined from the sequence analysis of trypic peptides and peptides generated by mild acid hydrolysis. Each component is composed of 44 amino acid residues, with evidence suggesting the presence of an N-terminal formylmethionine residue in each. The components I, II and III have respectively 33, 29 and 33 identical amino acid residues in their sequences, which represents 75%, 65.9% and 75% homology. These components contain a high proportion of hydrophobic amino acids, and their hydrophobicity profiles are closely related. Also, each of the three components contains a positively charged residue (lysine) as the third residue, followed by a core of hydrophobic residues. These results suggest that the three components are possible signal sequences of one or more secreted or membrane-associated proteins.

Amino Acid Sequence↗
PubMed1988

The basic study on kappa-lambda imaging by delta-curve for the detection of a monoclonal B-cell population in the peripheral blood.

Recently, kappa-lambda analysis with the "D" value was developed by Ault to detect a minor population of malignant B cells in peripheral blood. This analysis is based on the Kolmogorov-Smirnov test, and the D value is calculated by a flowcytometer and a computer. We have recently devised a more sensitive parameter for the kappa-lambda analysis than the D value called the delta-curve (delta c); the delta c applies the same principle as that of the D value. Mixing experiments with kappa-type and lambda-type chronic lymphocytic leukemia cells revealed that the delta c could not only detect a minor population of malignant kappa-B cells, but also that of malignant lambda-B cells using more sensitivity than the D value. A total of 49 blood samples obtained from 27 patients with various B-cell malignancies were investigated. D values were abnormal in 37% of all samples, while abnormal patterns of the delta c were recognized in 71%. On the other hand, 59% of samples obtained from the patients with B-cell lymphoma in aleukemic phase showed abnormal delta c, whereas D values exceeded the upper limit of the normal value in only 15% of the samples. It was suggested that the delta c could detect 3% to 7% of malignant B cells that were mixed with a population of normal lymphocytes.

B-Lymphocytes↗
PubMed1987

Induction and repair of DNA lesions in cultured human melanoma cells exposed to a nitrogen-ion beam.

Induction and repair kinetics of DNA lesions after exposure to nitrogen ions (N-ions) were studied in comparison to those after 180 kVp X-rays. DNA lesions in human melanoma cells (HMV-I) irradiated with 95 MeV N-ions (0-6 Gy, l.e.t.D = 530 keV micron-1 or with X-rays (0.9 Gy) were assayed by alkaline elution. The N-ion r.b.e. for DNA lesion induction was approximately 0.7. About 85 per cent of the lesions induced by N ions were rejoined with a time-course similar to the rejoining of DNA lesions produced by X-rays. These lesions were considered to be induced by delta-rays around the N-ion tracks. The fraction of residual DNA lesions remaining after a 6 h post-irradiation incubation was higher for N-ions than for X-rays. Unlike the case for X-rays, DNA-protein crosslinks were included in the residual DNA lesions after N-ion irradiation.

Cells, Cultured↗
PubMed1987

Purification and characterization of the extracellular alpha-amylase activity of the yeast Schwanniomyces alluvius.

The extracellular alpha-amylase activity of the yeast Schwanniomyces alluvius has been purified by anion-exchange chromatography on DEAE-cellulose and gel-filtration chromatography on Sephadex G-100. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and N-terminal amino acid analysis of the purified sample indicated that the enzyme preparation was homogeneous. The enzyme is a glycoprotein having a molecular mass of 52 kilodaltons (kDa) estimated by SDS-PAGE and 39 kDa by gel filtration on Sephadex G-100. Chromatofocusing shows that it is an acidic protein. It is resistant to trypsin but sensitive to proteinase K. Its activity is inhibited by the divalent cation chelators EDTA and EGTA and it is insensitive to sulfhydryl-blocking agents. Exogenous divalent cations are inhibitory as are high concentrations of monovalent salts. The enzyme has a pH optimum between 3.75 and 5.5 and displays maximum stability in the pH range of 4.0-7.0. Under the conditions tested, the activity is maximal between 45 and 50 degrees C and is very thermolabile. Analysis of its amino acid composition supports its acidic nature.

Amino Acids↗
PubMed1986

The purification and complete amino acid sequence of the 9000-Mr Ca2+-binding protein from rat placenta. Identity with the vitamin D-dependent intestinal Ca2+-binding protein.

A 9000-Mr Ca2+-binding protein was isolated from rat placenta and purified to homogeneity by h.p.l.c. procedures. The complete amino acid sequence was established for the 78-residue placental protein. A sequence analysis of a minor component of the rat intestinal Ca2+-binding protein (residues 4-78) and a tryptic peptide (residues 55-74), both purified by h.p.l.c., showed both proteins to be identical. Thus this placental 9000-Mr Ca2+-binding protein is the same gene product as the intestinal Ca2+-binding protein whose synthesis is dependent on vitamin D.

Amino Acid Sequence↗
PubMed1986

The primary structure of the ribosomal A-protein (L12) from the moderate halophile NRCC 41227.

The complete amino acid sequence of the ribosomal A-protein (equivalent to L7/L12 in Escherichia coli) from a moderate halophile, NRCC 41227, has been determined using an automatic Beckman sequencer and by the manual Edman cleavage of peptides obtained from selective proteolytic cleavage of the ribosomal A-protein. The protein contains 122 amino acids and has a composition of Asp5, Asn2, Thr6, Ser6, Glu21, Gln2, Pro2, Gly12, Ala21, Val14, Met4, Ile4, Leu9, Phe2, Lys11, and Arg1, and a molecular weight of 12 537. It has a net negative charge of -14 and is, therefore, slightly more acidic than other eubacterial ribosomal A-proteins. The phylogenetic tree, obtained by computer analysis of the amino acid sequence of this and other eubacterial A-proteins, indicate these proteins form five subgroups within the eubacterial kingdom. The moderate halophile NRCC 41227 is part of a group of Gram-negative bacteria that include E. coli and another moderate halophile Vibrio costicola. The sequence data provides further evidence that the moderate and extreme halophiles have evolved by separate pathways.

Amino Acid Sequence↗
PubMed1986

A clone coding for Schizophyllum commune beta-glucosidase: homology with a yeast beta-glucosidase.

Three identical clones coding for a partial sequence of the Schizophyllum commune beta-glucosidase were isolated from a cDNA library in lambda gt11, using polyclonal antibody to the enzyme. The identity was confirmed by comparison of the amino-terminus of a peptide from a protease lys-C digest with the sequence inferred from the cDNA sequence. A comparison of the sequence with that reported for a beta-glucosidase from Candida pelliculosa revealed a region in the latter with 43% identity in amino acid sequence. There was also a similarity in the S. commune beta-glucosidase to an active site sequence proposed for a S. commune endoglucanase, suggesting the possibility of a common catalytic mechanism for these two glucolytic enzymes.

Amino Acid Sequence↗
PubMed1985

Rat skin calcium-binding protein is parvalbumin.

Only one major low-Mr calcium-binding protein could be isolated by h.p.l.c. procedures from aqueous extracts of homogenized adult rat skin. This was shown by tryptic peptide mapping and independent amino acid sequence analysis to be identical in all 109 residues with the parvalbumin from rat skeletal muscle. This calcium-binding protein was not in skin epidermis, but was confined to the dermal layer. Skin calcium-binding protein is therefore parvalbumin.

Amino Acid Sequence↗