Single molecular insight into steric effect on C-terminal amino acids with various hydrogen bonding sites

Abstract Volatile anesthetics affect all cells and tissues tested, but their mechanisms and sites of action remain unknown. To gain insight into the cellular activities of anesthetics, we have isolated genes that, when overexpressed, render Saccharomyces cerevisiae resistant to the volatile anesthetic isoflurane. One of these genes, WAK3/TAT1, encodes a permease that transports amino acids including leucine and tryptophan, for which our wild-type strain is auxotrophic. This suggests that availability of amino acids may play a key role in anesthetic response. Multiple lines of evidence support this proposal: (i) Deletion or overexpression of permeases that transport leucine and/or tryptophan alters anesthetic response; (ii) prototrophic strains are anesthetic resistant; (iii) altered concentrations of leucine and tryptophan in the medium affect anesthetic response; and (iv) uptake of leucine and tryptophan is inhibited during anesthetic exposure. Not all amino acids are critical for this response since we find that overexpression of the lysine permease does not affect anesthetic sensitivity. These findings are consistent with models in which anesthetics have a physiologically important effect on availability of specific amino acids by altering function of their permeases. In addition, we show that there is a relationship between nutrient availability and ubiquitin metabolism in this response.

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Localization of the receptor-binding region of Clostridium perfringens enterotoxin utilizing cloned toxin fragments and synthetic peptides. The 30 C-terminal amino acids define a functional binding region

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)99124-6 ◽

1991 ◽

Vol 266 (17) ◽

pp. 11037-11043

Author(s):

P.C. Hanna ◽

T.A. Mietzner ◽

G.K. Schoolnik ◽

B.A. McClane

Keyword(s):

Amino Acids ◽

Clostridium Perfringens ◽

Receptor Binding ◽

Synthetic Peptides ◽

Binding Region ◽

Clostridium Perfringens Enterotoxin ◽

Terminal Amino ◽

Receptor Binding Region

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Epitope Mapping of Monoclonal Antibodies to Calreticulin Reveals That Charged Amino Acids Are Essential for Antibody Binding

Antibodies ◽

10.3390/antib10030031 ◽

2021 ◽

Vol 10 (3) ◽

pp. 31

Author(s):

Ann Christina Bergmann ◽

Cecilie Kyllesbech ◽

Rimantas Slibinskas ◽

Evaldas Ciplys ◽

Peter Højrup ◽

...

Keyword(s):

Amino Acids ◽

Monoclonal Antibodies ◽

Epitope Mapping ◽

Biological Function ◽

Specific Binding ◽

Enzyme Linked Immunosorbent Assay ◽

Potential Therapeutic Target ◽

Charged Amino Acids ◽

Chaperone Protein ◽

Terminal Amino

Calreticulin is a chaperone protein, which is associated with myeloproliferative diseases. In this study, we used resin-bound peptides to characterize two monoclonal antibodies (mAbs) directed to calreticulin, mAb FMC 75 and mAb 16, which both have significantly contributed to understanding the biological function of calreticulin. The antigenicity of the resin-bound peptides was determined by modified enzyme-linked immunosorbent assay. Specific binding was determined to an 8-mer epitope located in the N-terminal (amino acids 34–41) and to a 12-mer peptide located in the C-terminal (amino acids 362–373). Using truncated peptides, the epitopes were identified as TSRWIESK and DEEQRLKEEED for mAb FMC 75 and mAb 16, respectively, where, especially the charged amino acids, were found to have a central role for a stable binding. Further studies indicated that the epitope of mAb FMC 75 is assessable in the oligomeric structure of calreticulin, making this epitope a potential therapeutic target.

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TERMINAL AMINO ACIDS OF RHODOPSIN

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)70633-9 ◽

1957 ◽

Vol 229 (1) ◽

pp. 477-487

Author(s):

Genia Albrecht

Keyword(s):

Amino Acids ◽

Terminal Amino

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

International Journal of Molecular Sciences ◽

10.3390/ijms22031018 ◽

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.

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