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7 results on '"Haruki Kawai"'

1. Interaction of Receptor-Binding Domain of the SARS-CoV-2 Omicron Variant with hACE2 and Actin

Author

Ai Fujimoto, Haruki Kawai, Rintaro Kawamura, and Akira Kitamura

Subjects
COVID-19, spike protein, actin, fluorescence correlation spectroscopy, protein–protein interaction, Cytology, QH573-671
Abstract

The omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified in 2021 as a variant with heavy amino acid mutations in the spike protein, which is targeted by most vaccines, compared to previous variants. Amino acid substitutions in the spike proteins may alter their affinity for host viral receptors and the host interactome. Here, we found that the receptor-binding domain (RBD) of the omicron variant of SARS-CoV-2 exhibited an increased affinity for human angiotensin-converting enzyme 2, a viral cell receptor, compared to the prototype RBD. Moreover, we identified β- and γ-actin as omicron-specific binding partners of RBD. Protein complex predictions revealed that many omicron-specific amino acid substitutions affected the affinity between RBD of the omicron variant and actin. Our findings indicate that proteins localized to different cellular compartments exhibit strong binding to the omicron RBD.

Published
2024
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4. Studies on Hydroxy Amino Acids. VI. Formation of the Oxazoline Derivatives fromN-Acyl-β-hydroxy Amino Acid Peptides

Author

Michihiro Takai, Kenji Okawa, Haruki Kawai, and Kiichiro Nakajima

Subjects
chemistry.chemical_classification, chemistry.chemical_compound, Chemistry, Stereochemistry, Dehydroalanine, Hydantoin derivatives, Organic chemistry, lipids (amino acids, peptides, and proteins), General Chemistry, Oxazoline, Amino acid
Abstract

Oxazoline derivatives were mainly obtained from the O-tosyl-N-acyl-β-hydroxy amino acid peptides by β-elimination reaction. Dehydroalanine or hydantoin derivatives were isolated when the urethane type acyl groups were used.

Published
1977
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5. Studies on Hydroxy Amino Acids. IV. Syntheses of Several Peptides Containing Aziridinecarboxylic Acid Derived from the Corresponding Hydroxy Amino Acid Derivatives

Author

Kenji Okawa, Haruki Kawai, Takashi Tsuno, Kiichiro Nakajima, Yasuo Nakagawa, and Michio Iwai

Subjects
chemistry.chemical_classification, Stereochemistry, Acetoacetic ester synthesis, Peptide, General Chemistry, Aziridine, Amino acid, Serine, chemistry.chemical_compound, Elimination reaction, chemistry, Dehydroalanine, Organic chemistry, Threonine
Abstract

The β-elimination reaction of the O-tosyl β-hiydroxy amino acid peptide derivative was thoroughly investigated. The N-tosyl-L-serylglycine ester and the N-tosyl-L-threonylglycine ester gave the N-tosyl-L-aziridinecarbonyl-glycine ester and the N-tosyl-3-methyl-L-aziridinecarbonylglycine ester as the resulting products respectively by the elimination reaction. On the other hand, the N-carbobenzoxyglycyl-L-serylglycine ester was not converted into the aziridine peptide derivative; only the dehydroalanine peptide was obtained. However, the N-tosyl-L-phenylalanyl-L-threonylglycine ester and the N-carbobenzoxyglycyl-L-threonylglycine ester were converted into the corresponding aziridine peptide, and the N-tosyl-L-phenylalanyl-3-methyl-L-aziridinecarbonylglycine ester and the N-carbobenzoxyglycyl-3-methyl-L-aziridinecarbonylglycine ester were obtained respectively. It was concluded that the peptides containing threonine were easily converted into the aziridine peptides and not the serine peptides by the β-elimi...

Published
1972
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6. ChemInform Abstract: STUDIES ON HYDROXY AMINO ACIDS. VI. FORMATION OF THE OXAZOLINE DERIVATIVES FROM N-ACYL-β-HYDROXY AMINO ACID PEPTIDES

Author

Kenji Okawa, Kiichiro Nakajima, Haruki Kawai, and Michihiro Takai

Subjects
chemistry.chemical_classification, chemistry.chemical_compound, Chemistry, Dehydroalanine, Stereochemistry, Hydantoin derivatives, lipids (amino acids, peptides, and proteins), General Medicine, Oxazoline, Amino acid
Abstract

Oxazoline derivatives were mainly obtained from the O-tosyl-N-acyl-β-hydroxy amino acid peptides by β-elimination reaction. Dehydroalanine or hydantoin derivatives were isolated when the urethane type acyl groups were used.

Published
1977
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