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

Antibodies ◽  
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.

scholarly journals Monoclonal antibody studies of creatine kinase. The ART epitope: evidence for an intermediate in protein folding

1989 ◽  
Vol 257 (2) ◽  
pp. 461-469 ◽  
Author(s):  
G E Morris
Keyword(s):  
Amino Acids ◽  
Monoclonal Antibody ◽  
Creatine Kinase ◽  
Specific Binding ◽  
Trypsin Digestion ◽  
Proteinase K ◽  
Enzyme Linked Immunosorbent Assay ◽  
Muscle Creatine Kinase ◽  
Western Blots ◽  
Methionine Residues

Chemical cleavage at cysteine residues with nitrothiocyanobenzoic acid shows that the last 98 amino acids of the 380-amino-acid sequence of chick muscle creatine kinase are sufficient for binding of the monoclonal antibody CK-ART. Removal of the last 30 amino acids by cleavage at methionine residues with CNBr results in loss of CK-ART binding. CK-ART binding is also lost when these C-terminal methionine residues are oxidized to sulphoxide, but binding is regained on reduction. Proteinase K ‘nicks’ native CK at a single site near the C-terminus and two fragments of 327 amino acides and 53 amino acids can be separated by subsequent SDS or urea treatment. CK-ART still binds normally to ‘nicked’ CK, which is enzymically inactive. After treatment with either urea (in a competition enzyme-linked immunosorbent assay) or SDS (on Western blots), however, CK-ART binds to neither of the two fragments, although these treatments do not affect binding to intact CK. This suggests that parts of both CK fragments contribute to the CK-ART epitope. CK-ART is both species- and isoenzyme-specific, binding only to chick M-CK. The only C-terminal regions containing chick-specific sequences are residues 300-312 and residues 368-371, the latter group being close to the essential methionine residues. We suggest that one, or possibly both, of these regions is involved in forming the conformational epitope on the surface of the CK molecule which CK-ART recognizes. Native CK is resistant to trypsin digestion. The C-terminal half of urea-treated and partly-refolded CK is also resistant to trypsin digestion, whereas the N-terminal half is readily digested. The results suggest a C-terminal region which can refold more rapidly than the rest of the CK molecule and provide evidence for an intermediate in CK refolding.

scholarly journals Production of Monoclonal Antibodies Specific for the i and 1,2 Flagellar Antigens of Salmonella typhimurium and Characterization of Their Respective Epitopes

1998 ◽  
Vol 64 (12) ◽  
pp. 5033-5038 ◽  
Author(s):  
N. de Vries ◽  
K. A. Zwaagstra ◽  
J. H. J. Huis in’t Veld ◽  
F. van Knapen ◽  
F. G. van Zijderveld ◽  
...  
Keyword(s):  
Amino Acids ◽  
Monoclonal Antibodies ◽  
Salmonella Typhimurium ◽  
Immunosorbent Assay ◽  
Specific Antibody ◽  
Polyclonal Antibodies ◽  
Enzyme Linked Immunosorbent Assay ◽  
Specific Antibodies ◽  
Minimal Area

ABSTRACT Salmonella typhimurium expresses two antigenically distinct flagellins, each containing a different H antigen (i and 1,2), the combination of which is highly specific for this serotype. In this study, overlapping recombinant flagellin fragments were constructed from the fliC(H:i) and fljB (H:1,2) flagellin genes, and the expression products were tested for binding to H antigen-specific monoclonal and polyclonal antibodies. A minimal area, 86 amino acids for H:i and 102 amino acids for H:1,2, located in the central variable domain of each flagellin was required for the binding of serotype-specific antibodies, providing further evidence for the presence of a discontinuous H epitope. Two peptides comprising these areas were shown to be highly suitable for application as antigens in an enzyme-linked immunosorbent assay detecting S. typhimurium-specific antibody.

scholarly journals Mutagenesis of the HMGB (high-mobility group B) protein Cmb1 (cytosine-mismatch binding 1) of Schizosaccharomyces pombe: effects on recognition of DNA mismatches and damage

2003 ◽  
Vol 372 (2) ◽  
pp. 651-660 ◽  
Author(s):  
Christophe KUNZ ◽  
Karin ZURBRIGGEN ◽  
Oliver FLECK
Keyword(s):  
Amino Acids ◽  
Dna Binding ◽  
Schizosaccharomyces Pombe ◽  
Excision Repair ◽  
Specific Binding ◽  
High Mobility ◽  
High Mobility Group ◽  
Dna Mismatches ◽  
Terminal Amino ◽  
Group B

Cmb1 (cytosine-mismatch binding 1) is a high-mobility group (HMG) protein of Schizosaccharomyces pombe, which consists of 223 amino acids and has a single HMG domain at the C-terminal end. We have created several mutant and deletion forms of the Cmb1 protein and studied the effects on general DNA binding and specific binding to DNA mismatches and damaged DNA. Cmb1Δ41 (i.e. Cmb1 from which the 41 N-terminal amino acids have been deleted) bound specifically to cytosine-containing mismatches, to the cisplatin-induced intrastrand cross-links cis-GG and cis-AG and to an O6-methylguanine lesion. DNA binding was not affected when the 45 N-terminal amino acids were deleted, but was abolished in the absence of the 50 N-terminal amino acids, and was reduced when Cmb1 was truncated by between five and eleven C-terminal amino acids. Cmb1, both with and without the C-terminal truncations, retained its DNA binding affinity after heating at 95 °C. The cmb1 gene was induced when S. pombe cells were treated with cisplatin. Mitotic mutation rates were increased in a S. pombe cmb1 null mutant and in a cmb1-(1–212) mutant, which encodes a Cmb1 protein lacking the 11 C-terminal amino acids. We conclude that mutation avoidance by Cmb1 is distinct from Msh2-dependent mismatch repair, but related to nucleotide excision repair.

scholarly journals Epitope Mapping of Monoclonal Antibodies Capable of Neutralizing Cytotoxic Necrotizing Factor Type 1 of UropathogenicEscherichia coli

2001 ◽  
Vol 69 (4) ◽  
pp. 2066-2074 ◽  
Author(s):  
K. C. Meysick ◽  
M. Mills ◽  
A. D. O'Brien
Keyword(s):  
Amino Acids ◽  
Monoclonal Antibodies ◽  
Western Blot ◽  
Epitope Mapping ◽  
Biological Activities ◽  
Binding Domain ◽  
Cytotoxic Necrotizing Factor ◽  
Cell Assays ◽  
Factor Type

ABSTRACT Cytotoxic necrotizing factor type 1 (CNF1) of uropathogenicEscherichia coli belongs to a family of bacterial toxins that target the small GTP-binding Rho proteins that regulate the actin cytoskeleton. Members of this toxin family typically inactivate Rho; however, CNF1 and the highly related CNF2 activate Rho by deamidation. Other investigators have reported that the first 190 amino acids of CNF1 constitute the cellular binding domain and that the CNF1 enzymatic domain lies within a 300-amino-acid stretch in the C terminus of the toxin. Amino acids 53 to 75 appear to be critical for cell receptor recognition, while amino acids Cys866 and His881 are considered essential for deamidation activity. To delineate further the functional domains of CNF1, we generated 16 monoclonal antibodies (MAbs) against the toxin and used them for epitope mapping studies. Based on Western blot immunoreactivity patterns obtained from a series of truncated CNF1 proteins, this panel of MAbs mapped to epitopes located throughout the toxin, including the binding and enzymatic domains. All MAbs showed reactivity to CNF1 by Western and dot blot analyses. However, only 7 of the 16 MAbs exhibited cross-reactivity with CNF2. Furthermore, only three MAbs demonstrated the capacity to neutralize toxin in either HEp-2 cell assays (inhibition of multinucleation) or 5637 bladder cell assays (inhibition of cytotoxicity). Since CNF1 epitopes recognized by neutralizing MAbs are likely to represent domains or regions necessary for the biological activities of the toxin, the epitopes recognized by these three MAbs, designated JC4 (immunoglobulin G2a [IgG2a]), BF8 (IgA), and NG8 (IgG2a), were more precisely defined. MAbs JC4 and BF8 reacted with epitopes that were common to CNF1 and CNF2 and located within the putative CNF1 binding domain. MAb JC4 recognized an epitope spanning amino acids 169 to 191, whereas MAb BF8 mapped to an epitope between amino acids 135 and 164. Despite the capacity of both MAbs to recognize CNF2 in Western blot analyses, only MAb BF8 neutralized CNF2. MAb NG8 showed reactivity to a CNF1-specific epitope located between amino acids 683 and 730, a region that includes a very small portion of the putative enzymatic domain. Taken together, these findings identify three new regions of the toxin that appear to be critical for the biological activity of CNF1.

scholarly journals MAP1272c Encodes an NlpC/P60 Protein, an Antigen Detected in Cattle with Johne's Disease

2012 ◽  
Vol 19 (7) ◽  
pp. 1083-1092 ◽  
Author(s):  
John P. Bannantine ◽  
Cari K. Lingle ◽  
Judith R. Stabel ◽  
Kasra X. Ramyar ◽  
Brandon L. Garcia ◽  
...  
Keyword(s):  
Amino Acids ◽  
Monoclonal Antibodies ◽  
Recombinant Proteins ◽  
Binding Assay ◽  
Johne's Disease ◽  
Johne’S Disease ◽  
Integral Membrane Proteins ◽  
Enzyme Linked Immunosorbent Assay ◽  
Mycobacterial Species ◽  
Content Type

ABSTRACTThe protein encoded by MAP1272c has been shown to be an antigen ofMycobacterium aviumsubsp.paratuberculosisthat contains an NlpC/P60 superfamily domain found in lipoproteins or integral membrane proteins. Proteins containing this domain have diverse enzymatic functions that include peptidases, amidases, and acetyltransferases. The NlpC protein was examined in comparison to over 100 recombinant proteins and showed the strongest antigenicity when analyzed with sera from cattle with Johne's disease. To further localize the immunogenicity of NlpC, recombinant proteins representing defined regions were expressed and evaluated with sera from cattle with Johne's disease. The region from amino acids 74 to 279 was shown to be the most immunogenic. This fragment was also evaluated against a commercially available enzyme-linked immunosorbent assay (ELISA). Two monoclonal antibodies were produced in mice immunized with the full-length protein, and each recognized a distinct epitope. These antibodies cross-reacted with proteins from other mycobacterial species and demonstrated variable sizes of the proteins expressed from these subspecies. Both antibodies were further analyzed, and their interaction with MAP1272c and MAP1204 was characterized by a solution-based, luminescent binding assay. These tools provide additional means to study a strong antigen ofM. aviumsubsp.paratuberculosis.

scholarly journals Fine-structure epitope mapping of antierythropoietin monoclonal antibodies reveals a model of recombinant human erythropoietin structure

Blood ◽  
1996 ◽  
Vol 87 (7) ◽  
pp. 2702-2713 ◽  
Author(s):  
S Elliott ◽  
T Lorenzini ◽  
D Chang ◽  
J Barzilay ◽  
E Delorme ◽  
...  
Keyword(s):  
Amino Acids ◽  
Monoclonal Antibodies ◽  
Fine Structure ◽  
Recombinant Human Erythropoietin ◽  
Epitope Mapping ◽  
Conformational Epitope ◽  
Linear Epitope ◽  
Receptor Binding Domain ◽  
Mapping Data ◽  
Human Erythropoietin

We have isolated and mapped the rHuEPO epitopes for three noncompeting anti-EPO monoclonal antibodies (MoAbs). The MoAb 9G8A recognizes a linear epitope that includes amino acids 13, 16, and 17. MoAb F12 recognizes a conformational epitope that includes amino acids 31 through 33, 86 through 91, and 138. MoAb D11 recognizes a conformational epitope that includes amino acids 64 through 78 and 99 through 110. MoAb D11 neutralizes rHuEPO activity which suggests that its epitope may contain the receptor binding domain. Analysis of the effect of mutations on folding allowed the identification of buried residues, alpha-helical, and non alpha-helical regions. This data along with epitope mapping data of anti rHuEPO monoclonals was used to model rHuEPO protein structure. A model consistent with the data is a 4-helix bundle with short and long interconnecting loops.

Epitope mapping of monoclonal antibodies to bovine prolactin

1992 ◽  
Vol 263 (3) ◽  
pp. E520-E525 ◽  
Author(s):  
J. G. Scammell ◽  
D. N. Luck ◽  
D. L. Valentine ◽  
M. Smith
Keyword(s):  
Amino Acids ◽  
Monoclonal Antibodies ◽  
Western Blot ◽  
Blot Analysis ◽  
Epitope Mapping ◽  
Inhibitory Concentration ◽  
Specific Region ◽  
Amino Terminal ◽  
Carboxyl Terminal ◽  
Species Specific

The epitopes recognized by three monoclonal antibodies generated to sheep prolactin were determined by evaluating their cross-reactivities by immunodot analysis with 14 mutants of bovine prolactin, in which individual amino acids had been deleted or substituted. Mutations were made throughout the molecule and included disruption of the amino-terminal, carboxyl-terminal, and central disulfide loops. Lack of immunoreactivity was taken as an indication that the site of mutation was part of the epitope. Antibody 6F11 reacted with all bovine prolactin mutants tested, except those in which the carboxyl-terminal cysteine (position 199) was substituted by a serine. Antibodies 5G2 and 4C10 reacted with all of the bovine prolactin mutants, except those in which the amino-terminal cysteine (position 4) was substituted by a serine. Western blot analysis of sheep, squirrel monkey, and rat prolactins with the monoclonal antibodies revealed that 5G2 and 4C10 were specific for sheep prolactin, whereas antibody 6F11 cross-reacted with prolactins from all three species. The mitogenic activity of sheep or rat prolactin in the Nb2 bioassay was determined in the presence of the antibodies to determine whether the epitopes were part of the functional domains of these prolactins. The bioactivity of sheep prolactin (0.4 ng/ml) was unaffected by the monoclonal antibodies [0.01-1 microgram immunoglobulin G (IgG)/ml], whereas the bioactivity of rat prolactin (1.25 ng/ml) was inhibited by 6F11 with an apparent 50% inhibitory concentration of 0.25 microgram IgG/ml. These results indicate that monoclonal antibodies 5G2 and 4C10 cross-react with a species-specific region of the amino-terminal disulfide loop of bovine prolactin.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Borreliacidal OspC Antibodies Specific for a Highly Conserved Epitope Are Immunodominant in Human Lyme Disease and Do Not Occur in Mice or Hamsters

2005 ◽  
Vol 12 (6) ◽  
pp. 746-751 ◽  
Author(s):  
Steven D. Lovrich ◽  
Dean A. Jobe ◽  
Ronald F. Schell ◽  
Steven M. Callister
Keyword(s):  
Amino Acids ◽  
Lyme Disease ◽  
Surface Protein ◽  
Sensu Stricto ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
C Terminus ◽  
Lyme Disease Vaccine ◽  
Terminal Amino ◽  
Conserved Epitope

ABSTRACT Humans produce highly specific borreliacidal antibodies against outer surface protein C (OspC) shortly after infection with Borrelia burgdorferi sensu stricto. We previously demonstrated the epitope recognized by immunoglobulin M (IgM) and IgG OspC borreliacidal antibodies was located within the 50 amino acids nearest the carboxy (C) terminus. In this study, we show the immunodominant epitope is located in the highly conserved region within the seven C-terminal amino acids. Six early Lyme disease sera that contained borreliacidal activity and IgM and/or IgG OspC antibodies were chosen randomly and adsorbed with truncated OspC containing the 16 or 7 amino acids nearest the C terminus. Adsorptions with each truncated protein abrogated the borreliacidal activity completely. In addition, only small concentrations of OspC antibodies remained detectable by enzyme-linked immunosorbent assay and Western blotting. Moreover, borreliacidal OspC antibodies were not induced in laboratory mice or hamsters despite heavy infections with B. burgdorferi spirochetes. These findings confirm that borreliacidal antibodies comprise the majority of the IgM and IgG OspC antibody response in human Lyme disease and that the epitope is located in the highly conserved C terminus. In addition, rodent animal models appear to be inappropriate subjects for assessing the effectiveness of the epitope for serodiagnosis or as a human Lyme disease vaccine.

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