The Chemical Cross-Linking of Peptide Chains
Roger L. Lundblad, Claudia M. Noyes in Chemical Reagents for Protein Modification, 1984
The next general class of reagents that we will discuss is the homobifunctional imidoesters (Figure 8). This class of reagents was introduced by Singer and co-workers.35 These reagents have the advantage that the reaction with the protein results in charge preservation of the lysine residue modified. This class of reagents is highly specific for primary amines in the following reactions as shown in Figures 9 and 10. Aspects of the chemistry of this reaction are further discussed in Volume I, Chapter 10. Buffer effects on the reaction have not been extensively investigated except to specify that the use of potential competing nucleophiles (e.g., Tris, imidazole) should be avoided. Most studies have used 0.02 to 0.1 M triethanolamine in the range of pH 8.0 to 9.0. It has been suggested that the amidation reaction is enhanced by the presence of triethanolamine in studies on the reaction of methyl-4-mercaptobutyrimidate.22 The greatest use of these reagents has been in the study of protomer organization of oligomeric proteins and self-association systems.
The Chemical Cross-Linking of Peptide Chains
Roger L. Lundblad, Claudia M. Noyes in Chemical Reagents for Protein Modification, 1984
The next general class of reagents that we will discuss is the homobifunctional imidoesters (Figure 8). This class of reagents was introduced by Singer and co-workers.35 These reagents have the advantage that the reaction with the protein results in charge preservation of the lysine residue modified. This class of reagents is highly specific for primary amines in the following reactions as shown in Figures 9 and 10. Aspects of the chemistry of this reaction are further discussed in Volume I, Chapter 10. Buffer effects on the reaction have not been extensively investigated except to specify that the use of potential competing nucleophiles (e.g., Tris, imidazole) should be avoided. Most studies have used 0.02 to 0.1 M triethanolamine in the range of pH 8.0 to 9.0. It has been suggested that the amidation reaction is enhanced by the presence of triethanolamine in studies on the reaction of methyl-4-mercaptobutyrimidate.22 The greatest use of these reagents has been in the study of protomer organization of oligomeric proteins and self-association systems.
The Chemical Cross-Linking Of Peptide Chains
Roger L. Lundblad in Chemical Reagents for Protein Modification, 2020
Homobifunctional imidoesters (Figure 8) were introduced by Singer and co-workers.47 These reagents have the advantage that the reaction with the protein results in charge preservation of the lysine residue modified. This class of reagents is highly specific for primary amines in the following reactions as shown in Figures 9 and 10. Aspects of the chemistry of this reaction are discussed further in Chapter 10. Buffer effects on the reaction have not been extensively investigated except to specify that the use of potential competing nucleophiles (e.g., Tris, imidazole) should be avoided. Most studies have used 0.02 to 0.1 M triethanolamine in the range of pH 8.0 to 9.0. It has been suggested that the amidation reaction is enhanced by the presence of triethanolamine in studies on the reaction of methyl-4-mercaptobutyrimidate.31 The greatest use of these reagents has been in the study of protomer organization of oligomeric proteins and self-association systems.
Epidemiology, pathogenesis, clinical presentations, diagnosis and treatment of COVID-19: a review of current evidence
Published in Expert Review of Clinical Pharmacology, 2021
Sayeeda Rahman, Maria Teresa Villagomez Montero, Kherie Rowe, Rita Kirton, Frank Kunik
Coronaviruses get their name from the characteristic feature of their S protein, which resembles a halo effect seen in solar eclipse or a crown-like appearance under an electron microscope [34]. The S protein has a roughly cylindrical shape and is heavily glycosylated [40], and encodes and possesses both receptor-binding and-fusion functions. Coronavirus uses its S protein, a main target for neutralizing antibodies, to bind with specific receptors and mediate membrane fusion and virus entry. It is a trimeric protein [34], composed of three intertwined chains that have identical amino acid sequences, each of which is called a protomer. However, the protomers do not have identical three-dimensional conformations. The monomer of the trimeric S protein is approximately 180 kDa and contains two distinct functional subunits, S1 and S2, both necessary for mediating attachment and membrane fusion, respectively. In its structure, N- and C-terminal portions of the S1 fold are two independent domains, the N-terminal domain (NTD) and C-terminal domain (CTD). Depending on the virus, either NTD or CTD can serve as the receptor-binding domain (RBD). The S protein induces successful infusion into the cell by first binding to the host receptor through the RBD of the S1 subunit, resulting in viral genomic fusion; the second stage by S2 facilitates the fusion of the cell and host membranes, which contains amino acid sequences necessary for continuing infiltration [41–43]. The RBD in the S protein is the most mutable part of the coronavirus genome and tends to be common for general viruses [44].
Human rhinovirus infection and COPD: role in exacerbations and potential for therapeutic targets
Published in Expert Review of Respiratory Medicine, 2020
John Cafferkey, James Andrew Coultas, Patrick Mallia
Human rhinoviruses are positive-sense, single-stranded RNA viruses of which there are 3 species or genotypes. These include 74 serotypes of HRV-A, 25 serotypes of HRV-B and 60 strains of the more recently discovered HRV-C group, producing around 160 serotypes in total [72,73]. Serotypes vary according to differences in the RNA sequence and capsid [74]. HRV lack the genome proofreading mechanisms present in most eukaryotic cells resulting in a high rate of mutation and huge antigenic diversity. The virus genome consists of a 5ʹUTR (un-translated region), P1, P2 and P3 regions and ends in a poly-A tail [74]. The whole virus genome comprises a single gene and its translated polyprotein is cleaved by viral proteases to produce 11 separate proteins (Figure 1) [75]. Protease 2A performs the first cleavage to release the P1 protein from the polyprotein, and protease 3C completes the remaining cleavage events. Of most importance are the structural viral proteins (VP) contained within the P1 protein – VP1, VP2, VP3 and VP4. These produce the viral capsid that protects its genetic contents and are the principle targets of the immune system [74]. The VP proteins form a protomer unit which is assembled into 12 pentamers producing an icosahedral shape. Encroaching each central plane of the capsid is a canyon-possessing VP1 protein in which specific amino acid sequences form host binding sites [76].
Foot and mouth disease vaccine strain selection: current approaches and future perspectives
Published in Expert Review of Vaccines, 2018
The causative agent of FMD is foot and mouth disease virus (FMDV), a member of the genus Aphthovirus in the family Picornaviridae. It is a nonenveloped single stranded positive sense RNA virus containing a genome, ~ 8.3 kb in length enclosed in a viral capsid [5]. The genome contains a single open reading frame (ORF) that codes for four structural (VP1–4) and 8–10 non-structural proteins. The viral capsid comprises 60 copies of each of the 4 structural proteins. One copy of each of the structural protein form a protomer, 5 protomers form a pentamer, and 12 pentamers form the complete capsid. VP1, 2 and 3 are on the surface of the virus and are comprised essentially of 8 antiparallel β sheets linked to each other by loop structures to form a β barrel, whereas VP4 is internal and has little secondary structure [5].
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