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Biomedical subjects

M Yaguchi

Publications and source records attributed to M Yaguchi.

At least 127 records · Page 7Linked to original sources
PubMed1975

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↗
PubMed1975

The conservation of amino acids in the n-terminal position of ribosomal and cytosol proteins from Escherichia coli, Bacillus stearothermophilus, and Halobacterium cutirubrum.

Alanine, methionine, and serine are the predominant N-terminal residues in the cytosol and ribosomal protein fractions from the thermophile Bacillus stear othermophilus and the extreme halophile Halobacterium cutirubrum, a similar situation to that previously found in Escherichia coli. In all three bacteria the N-terminal residues of the 30S ribosomal proteins are mainly alanine greater than methionine greater than serine whereas in the 50S ribosomal proteins from E. coli and B. stearothermophilus the predominant residues are methionine greater than alanine greater than serine suggesting conservation of specific N-terminal residues in these ribosomal proteins. However, the 50S ribosomal proteins from H. cutirubrum showed serine as the major N-terminal residue.

Amino Acid Sequence↗
PubMed1972

Halobacterium cutirubrum ribosomes. Properties of the ribosomal proteins and ribonucleic acid.

1. The 30S ribosomal subunit of the extreme halophile Halobacterium cutirubrum is unstable and loses 75% of its ribosomal protein when the 70S ribosome is dissociated into the two subunits. A stable 30S subunit is obtained if the dissociation of the 70S particle is carried out in the presence of the soluble fraction. 2. A fractionation procedure was developed for the selective removal of groups of proteins from the 30S and 50S subunits. When the ribosomes, which are stable in 4m-K(+) and 0.1m-Mg(2+), were extracted with low-ionic-strength buffer 75-80% of the 30S proteins and 60-65% of the 50S proteins as well as the 5S rRNA were released. The proteins in this fraction are the most acidic of the H. cutirubrum ribosomal proteins. Further extraction with Li(+)-EDTA releases additional protein, leaving a core particle containing either 16S rRNA or 23S rRNA and about 5% of the total ribosomal protein. The amino acid composition, mobility on polyacrylamide gels at pH4.5 and 8.7, and the molecular-weight distribution of the various protein fractions were determined. 3. The s values of the rRNA are 5S, 16S and 23S. The C+G contents of the 16S and 23S rRNA were 56.1 and 58.8% respectively and these are higher than C+G contents of the corresponding Escherichia coli rRNA (53.8 and 54.1%).

Amino Acids↗