Carboxyl-Terminal Sequences of Procaryotic Ribosomal Proteins from Escherichia coli, Bacillus stearothermophilus, and Halobacterium cutirubrum

1975 ◽  
Vol 53 (8) ◽  
pp. 827-833 ◽  
Author(s):  
Ronald G. Duggleby ◽  
Harvey Kaplan ◽  
Louis Peter Visentin
Keyword(s):  
Escherichia Coli ◽  
Ribosomal Proteins ◽  
Bacillus Stearothermophilus ◽  
Chain Termination ◽  
Amino Acid Sequences ◽  
Structural Homology ◽  
Terminal Amino Acid ◽  
E Coli ◽  
Terminal Amino ◽  
Carboxyl Terminal

The carboxyl-terminal amino acid sequences of two ribosomal proteins, Escherichia coli L12 and E. coli S4, and the proteins believed to be their equivalents from Bacillus stearothermophilus and Halobacterium cutirubrum, were determined. These proteins are known to be required for peptide chain termination (L12) and in ribosome assembly (S4). The carboxyl-terminal sequences obtained suggest that the E. coli and B. stearothermophilus proteins have retained structural homology in this region, whereas the H. cutirubrum proteins have not.

scholarly journals Roles of the C-Terminal Amino Acids of Non-Hexameric Helicases: Insights from Escherichia coli UvrD

2021 ◽  
Vol 22 (3) ◽  
pp. 1018
Author(s):  
Hiroaki Yokota
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Amino Acid ◽  
Single Molecule ◽  
Underlying Mechanism ◽  
Amino Acid Sequences ◽  
E Coli ◽  
X Ray Crystallography ◽  
Terminal Amino

Helicases are nucleic acid-unwinding enzymes that are involved in the maintenance of genome integrity. Several parts of the amino acid sequences of helicases are very similar, and these quite well-conserved amino acid sequences are termed “helicase motifs”. Previous studies by X-ray crystallography and single-molecule measurements have suggested a common underlying mechanism for their function. These studies indicate the role of the helicase motifs in unwinding nucleic acids. In contrast, the sequence and length of the C-terminal amino acids of helicases are highly variable. In this paper, I review past and recent studies that proposed helicase mechanisms and studies that investigated the roles of the C-terminal amino acids on helicase and dimerization activities, primarily on the non-hexermeric Escherichia coli (E. coli) UvrD helicase. Then, I center on my recent study of single-molecule direct visualization of a UvrD mutant lacking the C-terminal 40 amino acids (UvrDΔ40C) used in studies proposing the monomer helicase model. The study demonstrated that multiple UvrDΔ40C molecules jointly participated in DNA unwinding, presumably by forming an oligomer. Thus, the single-molecule observation addressed how the C-terminal amino acids affect the number of helicases bound to DNA, oligomerization, and unwinding activity, which can be applied to other helicases.

Purification, properties, and N-terminal amino acid sequence of certain 50S ribosomal subunit proteins from the archaebacterium Halobacterium cutirubrum

1984 ◽  
Vol 62 (6) ◽  
pp. 426-433 ◽  
Author(s):  
Alastair T. Matheson ◽  
Makoto Yaguchi ◽  
Patricia Christensen ◽  
C. Fernand Rollin ◽  
Sadiq Hasnain
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Sequence Homology ◽  
Ribosomal Proteins ◽  
Large Subunit ◽  
Ribosomal Subunit ◽  
Terminal Amino Acid ◽  
Terminal Amino ◽  
Terminal Amino Acid Sequence

Sixteen ribosomal proteins (r-proteins) from the 50S ribosomal subunit of the archaebacterium Halobacterium cutirubrum have been purified and their amino acid composition and partial N-terminal amino acid sequence have been determined. These proteins as a group are much more acidic than the large subunit r-proteins from eubacteria or eukaryotes. Little sequence homology is evident between the 50S subunit archaebacterial r-proteins and the equivalent proteins from the eubacterium Escherichia coli.

Kynurenine aminotransferase and glutamine transaminase K of Escherichia coli: identity with aspartate aminotransferase

2001 ◽  
Vol 360 (3) ◽  
pp. 617-623 ◽  
Author(s):  
Qian HAN ◽  
Jianmin FANG ◽  
Jianyong LI
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Aspartate Aminotransferase ◽  
Expression System ◽  
Xanthurenic Acid ◽  
Amino Acid Residues ◽  
Terminal Amino Acid ◽  
Kynurenine Aminotransferase ◽  
E Coli ◽  
Terminal Amino

The present study describes the isolation of a protein from Escherichia coli possessing kynurenine aminotransferase (KAT) activity and its identification as aspartate aminotransferase (AspAT). KAT catalyses the transamination of kynurenine and 3-hydroxykynurenine to kynurenic acid and xanthurenic acid respectively, and the enzyme activity can be easily detected in E. coli cells. Separation of the E. coli protein possessing KAT activity through various chromatographic steps led to the isolation of the enzyme. N-terminal sequencing of the purified protein determined its first 10 N-terminal amino acid residues, which were identical with those of the E. coli AspAT. Recombinant AspAT (R-AspAT), homologously expressed in an E. coli/pET22b expression system, was capable of catalysing the transamination of both l-kynurenine (Km = 3mM; Vmax = 7.9μmol·min−1·mg−1) and 3-hydroxy-dl-kynurenine (Km = 3.7mM; Vmax = 1.25μmol·min−1·mg−1) in the presence of pyruvate as an amino acceptor, and exhibited its maximum activity at temperatures between 50–60°C and at a pH of approx. 7.0. Like mammalian KATs, R-AspAT also displayed high glutamine transaminase K activity when l-phenylalanine was used as an amino donor (Km = 8mM; Vmax = 20.6μmol·min−1·mg−1). The exact match of the first ten N-terminal amino acid residues of the KAT-active protein with that of AspAT, in conjunction with the high KAT activity of R-AspAT, provides convincing evidence that the identity of the E. coli protein is AspAT.

The Conservation of Amino Acids in the N-Terminal Position of Ribosomal and Cytosol Proteins from Escherichia coli, Bacillus stearothermophilus, and Halobacterium cutirubrum

1975 ◽  
Vol 53 (12) ◽  
pp. 1323-1327 ◽  
Author(s):  
Alastair T. Matheson ◽  
Makoto Yaguchi ◽  
Louis P. Visentin
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Bacillus Stearothermophilus ◽  
Protein Fractions ◽  
Extreme Halophile ◽  
Terminal Position ◽  
E Coli ◽  
Terminal Residue

Alanine, methionine, and serine are the predominant N-terminal residues in the cytosol and ribosomal protein fractions from the thermophile Bacillus stearothermophilus 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 [Formula: see text] methionine > serine whereas in the 50S ribosomal proteins from E. coli and B. stearothermophilus the predominant residues are methionine > alanine > 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.

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