scholarly journals Subunit interacting surfaces of human haemoglobin. Localization of the α-subunit-β-subunit interacting surfaces on the β-chain by a comprehensive synthetic strategy

1986 ◽  
Vol 234 (2) ◽  
pp. 457-461 ◽  
Author(s):  
N Yoshioka ◽  
M Z Atassi
Keyword(s):  
Binding Capacity ◽  
Binding Activity ◽  
The Other ◽  
Synthetic Approach ◽  
Beta Chain ◽  
Human Haemoglobin ◽  
Α Subunit ◽  
Alpha Chain ◽  
Synthetic Strategy ◽  
Interacting Surfaces

A synthetic approach is introduced for localization of subunit interacting surfaces in oligomeric proteins. It consists of studying the binding activity of consecutive uniform overlapping peptides encompassing an entire subunit to the other, radiolabelled, subunit. This permits the establishment of the full profile of peptides that bind the other intact subunit. This approach has been demonstrated with haemoglobin, and its application here with the beta-chain peptides has enabled the localization on the beta-chain of the submolecular regions responsible for its binding to alpha-chain in solution. There was good agreement between the binding surfaces found here in solution and those expected from the crystal structure. There were also, however, some significant differences in the levels of binding found in solution and those expected from the crystal. Peptide 21-35 possessed much higher binding activity than would be expected from its contribution to subunit association in the crystal. Conversely, other regions expected to possess considerable binding capacity for alpha-chain either showed low (peptides 111-125 and 121-135) or almost no binding (peptides 91-105 and 101-115) capacity. On the other hand, two interacting surfaces (within peptides 11-25 and 71-85) that make a contribution in solution do not appear to play a role in the crystal. It is concluded that the regions of subunit association in solution are close to, but not identical with, those in the crystal. The approach should serve as an effective method for localization of subunit interacting surfaces of unknown proteins, even those that can be isolated only in traces.

scholarly journals Haemoglobin binding with haptoglobin. Localization of the haptoglobin-binding sites on the β-chain of human haemoglobin by synthetic overlapping peptides encompassing the entire chain

1986 ◽  
Vol 234 (2) ◽  
pp. 453-456 ◽  
Author(s):  
N Yoshioka ◽  
M Z Atassi
Keyword(s):  
Binding Sites ◽  
Solid Phase ◽  
Three Dimensional ◽  
Binding Activity ◽  
Dimensional Structure ◽  
Synthetic Approach ◽  
Protein Chain ◽  
Beta Chain ◽  
Human Haemoglobin ◽  
Β Chain

A synthetic approach was employed to identify the haptoglobin-binding sites on the beta-chain of human haemoglobin. This approach consists of the synthesis of a series of consecutive overlapping peptides that, together, systematically represent the entire protein chain. Fourteen synthetic peptides (beta 1-15, beta 11-25 etc.) were examined for their ability to bind human haptoglobin by quantitative solid-phase radiometric titrations of 125I-labelled haptoglobin. Of these 14 peptides only peptides beta 11-25 and beta 131-146 bound haptoglobin significantly; peptide beta 21-35 exhibited a small binding activity as a consequence of the overlap with peptide beta 11-25. On this basis and by examination of the three-dimensional structure of haemoglobin, it was concluded that the beta-chain of haemoglobin has two binding sites for haptoglobin that reside in, but do not necessarily encompass all of, the regions beta 11-25 and beta 131-146.

scholarly journals Antigenic structure of human haemoglobin. Localization of the antigenic sites of the β-chain in three host species by synthetic overlapping peptides representing the entire chain

1986 ◽  
Vol 234 (2) ◽  
pp. 441-447 ◽  
Author(s):  
N Yoshioka ◽  
M Z Atassi
Keyword(s):  
Host Species ◽  
Structural Characteristics ◽  
Three Dimensional ◽  
Antigenic Structure ◽  
Synthetic Approach ◽  
Immune Recognition ◽  
Beta Chain ◽  
Human Haemoglobin ◽  
Antigenic Sites ◽  
Full Profile

A comprehensive synthetic approach is applied here to localize the continuous antigenic sites of the beta-chain of haemoglobin. The approach was based on the synthesis and purification of the following consecutive 15-residue peptides (each overlapping by five residues at both ends with the peptides preceding it and following it in the sequence): 1-15, 11-25 etc. Quantitative radiometric titrations of protein and peptide adsorbents were performed with 125I-labelled anti-haemoglobin antibodies from three different host species. The specificity of antibody binding to peptide adsorbents was confirmed by inhibition studies and by the binding specificity of antibodies isolated from peptide adsorbents. These studies established the full profile of antigenic beta-chain regions, which was found to be independent of the host species. Five major antigenic sites were localized, and their three-dimensional and structural characteristics are discussed in relation to the immune recognition of haemoglobin and other proteins.

scholarly journals Structurally inherent antigenic sites. Localization of the antigenic sites of the α-chain of human haemoglobin in three host species by a comprehensive synthetic approach

1982 ◽  
Vol 203 (1) ◽  
pp. 201-208 ◽  
Author(s):  
A L Kazim ◽  
M Z Atassi
Keyword(s):  
Primary Structure ◽  
Host Species ◽  
Three Dimensional ◽  
Antigenic Structure ◽  
Synthetic Approach ◽  
Human Haemoglobin ◽  
Alpha Chain ◽  
Antigenic Sites ◽  
Full Profile ◽  
Related Proteins

The antigenic structure of the alpha-chain of human haemoglobin was studied by a synthetic approach consisting of the synthesis of a series of consecutive overlapping peptides that together systematically represent the entire primary structure of the protein. This approach enabled the identification of a full profile of immunochemically active alpha-chain peptides and the localization of its major ‘continuous’ antigenic sites. Antibodies to haemoglobin raised in each of three different species (goat, rabbit and mouse) recognize similar sites on the alpha-chain. Further, the molecular locations of these sites coincide with alpha-chain regions extrapolated from antigenic sites of the conformationally similar myoglobin molecule. These findings support our earlier proposed concept of ‘structurally inherent antigenic sites’, namely that antigenicity is conferred on certain surface regions of proteins by virtue of their three-dimensional locations. Thus the antigenic sites of conformationally related proteins are likely to have similar molecular locations.

scholarly journals A novel and comprehensive synthetic approach for the elucidation of protein antigenic structures. Determination of the full antigenic profile of the α-chain of human haemoglobin

1980 ◽  
Vol 191 (1) ◽  
pp. 261-264 ◽  
Author(s):  
A L Kazim ◽  
M Z Atassi
Keyword(s):  
Primary Structure ◽  
Synthetic Approach ◽  
Human Haemoglobin ◽  
Alpha Chain ◽  
Antigenic Sites ◽  
Full Profile ◽  
Α Chain ◽  
First Time ◽  
Antigenic Profile

A comprehensive synthetic approach for the determination of continuous antigenic sites of proteins is presented. This approach consists of the synthesis of a series of consecutive overlapping peptides that, together, systematically represent the entire primary structure of the protein under study. Its application to the alpha-chain of human haemoglobin afforded, for the first time, a full profile of immunochemically active alpha-chain peptides and enabled the localization of all the major continuous antigenic sites of this haemoglobin subunit.

Functional Pool of Cyclic Adenosine 3',5'-Monophosphate in Rabbit Platelets

1983 ◽  
Vol 49 (01) ◽  
pp. 008-012 ◽  
Author(s):  
Shuichi G Hashimoto
Keyword(s):  
Plasma Membrane ◽  
Cyclic Amp ◽  
Binding Capacity ◽  
Binding Activity ◽  
The Other ◽  
Rabbit Platelet ◽  
Platelet Membranes ◽  
Other Hand ◽  
Fraction I ◽  
Induced Aggregation

SummaryAccumulation of the newly formed 14C-cyclic adenosine 3',5’-monophosphate (cyclic AMP) was found in the P1 (1.0) fraction, i. e. a platelet plasma membrane fraction which was obtained from 14C-adenine-labeled platelets. On the other hand, total cyclic AMP as determined simultaneously was located mainly in the platelet soluble fraction. Furthermore, the highest value of the cyclic AMP-binding capacity was found in the P1 (1.0) fraction. The cyclic AMP-binding activity of platelet membranes was attributed to two proteins with molecular weights of approximately 48,000 and 68,000.The treatment of 14C-adenine-prelabeled platelets with thrombin (1 unit per ml) led to about 40% decrease in the newly formed 14C-cyclic AMP level and 18% reduction of 14C-adenosine triphosphate level in whole platelets within 10 sec. On the other hand, the 14C-cyclic AMP level in the P, fraction decreased by about 80% of the control value while the total cyclic AMP in this fraction was almost unchanged. This rapid and striking fall in the membrane 14C-cyclic AMP level could be correlated with the more than 2fold stimulation of the membrane-bound cyclic AMP phosphodiesterase, together with the more than 20% inhibition of both the cyclic AMP-binding capacity and the adenyl cyclase in platelet membranes by thrombin treatment. These observations suggest the possibility that functional pool of cyclic AMP related to thrombin-induced aggregation is located in rabbit platelet plasma membrane.

scholarly journals Haemoglobin binding with haptoglobin. Localization of the haptoglobin-binding site on the α-chain of human haemoglobin

1981 ◽  
Vol 197 (2) ◽  
pp. 507-510 ◽  
Author(s):  
A L Kazim ◽  
M Z Atassi
Keyword(s):  
Binding Site ◽  
Synthetic Approach ◽  
Protein Chain ◽  
Human Haemoglobin ◽  
Alpha Chain ◽  
Α Chain

A synthetic approach was employed to identify the haptoglobin-binding site on the alpha-chain of human haemoglobin. This approach cosists of the synthesis of a series of consecutive overlapping peptides that, together, systematically represent the entire protein chain. Fourteen peptides were synthesized (alpha 1-15, alpha 11-25, alpha 21-35, alpha 31-45, alpha 41-55, alpha 51-65, alpha 61-75, alpha 71-85, alpha 81-95, alpha 91-105, alpha 101-115, alpha 111-125, alpha 121-135 and alpha 131-141), and their ability bind human haptoglobin was studied, Only peptide alpha 121-135 bound haptoglobin significantly. On this basis we conclude that the haptoglobin-binding site on the alpha-chain of haemoglobin resides within, but does not necessarily encompass all of, the region alpha 121-135.

scholarly journals Carboxymethylation of methionine residues in bovine pituitary luteinizing hormone and its subunits. Location of specifically modified methionine residues

1976 ◽  
Vol 159 (1) ◽  
pp. 79-87 ◽  
Author(s):  
K W Cheng
Keyword(s):  
Luteinizing Hormone ◽  
Gel Filtration ◽  
Receptor Site ◽  
Iodoacetic Acid ◽  
Binding Activity ◽  
Beta Subunits ◽  
Beta Chain ◽  
Tryptic Peptides ◽  
Alpha Chain ◽  
Methionine Residues

Bovine lutropin (luteinizing hormone) was carboxymethylated at pH3.0 for 12 h at 37 degrees C with iodoacetic acid for specific modification of methionine residues. To facilitate the location of preferentially modified methionine residues, iodoE114C]acetic acid was added as tracer. The alpha and beta subunits of bovine lutropin were carboxymethylated with a 2- or 5-fold molar excess of iodoacetic acid either in the presence or absence of their counterpart subunits. The modified subunits were separated and isolated by counter-current distribution followed by gel filtration on Sephadex G-100. To locate the modified methiones, the isolated alpha or beta chain was reduced. S-carboxymethylated and subjected to tryptic hydrolysis. The tryptic peptides were fractionated by gel filtration on Bio-Gel P-10. From analyses of the purified 14C-labelled tryptic peptides, it was observed that methionine-8 and -33 in bovine lutropin alpha chain and methionine-52 in the beta chain were preferentially modified. Similar results were obtained when isolated alpha and beta subunits were individually carboxymethylated in the absence of their counterpart subunit under identical conditions. The fact that a recombinant of native human lutropin alpha chain, in which a valine residue is present in the position corresponding to methionine-8 of bovine lutropin alpha chain, and carboxymethylated bovine lutropin beta chain regenerated a substantial amount of receptor-site-binding activity indicated that methionine-8 in bovine alpha chain was biologically not essential. These studies showed clearly that both methionine-33 in the alpha chain and methionine-52 in the beta subunit were involved for optimum binding between bovine lutropin and its receptors for expression of hormonal activity.

scholarly journals Haemoglobin binding with haptoglobin. Unequivocal demonstration that the β-chains of human haemoglobin bind to haptoglobin

1980 ◽  
Vol 185 (1) ◽  
pp. 285-287 ◽  
Author(s):  
A L Kazim ◽  
M Z Atassi
Keyword(s):  
Solid Phase ◽  
Beta Chain ◽  
Human Haemoglobin ◽  
Alpha Chain ◽  
Highly Sensitive ◽  
Radiometric Assay

Haptoglobin binding to haemoglobin and its isolated alpha- and beta-chains was studied by use of a highly sensitive solid-phase radiometric assay. As expected, adsorbents of haemoglobin bound 125I-labelled haptoglobin more efficiently than did adsorbents of the alpha-chain. However, unexpectedly, adsorbents of the beta-chain were found to be essentially identical with those of the alpha-chain in their ability to bind haptoglobin. These results demonstrate, unequivocally, the ability of beta-chains to bind to haptoglobin, and indicate that this assay is particularly convenient and useful for studying haptoglobin interactions with haemoglobin and its alpha- and beta-chains.

scholarly journals A critical cytoplasmic domain of the interleukin-5 (IL-5) receptor alpha chain and its function in IL-5-mediated growth signal transduction.

1994 ◽  
Vol 14 (11) ◽  
pp. 7404-7413 ◽  
Author(s):  
S Takaki ◽  
H Kanazawa ◽  
M Shiiba ◽  
K Takatsu
Keyword(s):  
Signal Transduction ◽  
Protein Tyrosine Kinase ◽  
Cytoplasmic Domain ◽  
Beta Chain ◽  
Cytoplasmic Domains ◽  
Interleukin 5 ◽  
Alpha Chain ◽  
Gm Csf ◽  
Response Expression ◽  
And Function

Interleukin-5 (IL-5) regulates the production and function of B cells, eosinophils, and basophils. The IL-5 receptor (IL-5R) consists of two distinct membrane proteins, alpha and beta. The alpha chain (IL-5R alpha) is specific to IL-5. The beta chain is the common beta chain (beta c) of receptors for IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF). The cytoplasmic domains of both alpha and beta chains are essential for signal transduction. In this study, we generated cDNAs of IL-5R alpha having various mutations in their cytoplasmic domains and examined the function of these mutants by expressing them in IL-3-dependent FDC-P1 cells. The membrane-proximal proline-rich sequence of the cytoplasmic domain of IL-5R alpha, which is conserved among the alpha chains of IL-5R, IL-3R, and GM-CSF receptor (GM-CSFR), was found to be essential for the IL-5-induced proliferative response, expression of nuclear proto-oncogenes such as c-jun, c-fos, and c-myc, and tyrosine phosphorylation of cellular proteins including JAK2 protein-tyrosine kinase. In addition, analysis using chimeric receptors which consist of the extracellular domain of IL-5R alpha and the cytoplasmic domain of beta c suggested that dimerization of the cytoplasmic domain of beta c may be an important step in activating the IL-5R complex and transducing intracellular growth signals.

scholarly journals A comprehensive analysis of novel disulfide bond introduction site into the constant domain of human Fab

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hitomi Nakamura ◽  
Moeka Yoshikawa ◽  
Naoko Oda-Ueda ◽  
Tadashi Ueda ◽  
Takatoshi Ohkuri
Keyword(s):  
Thermal Stability ◽  
Pichia Pastoris ◽  
Protein Stability ◽  
Disulfide Bond ◽  
Binding Activity ◽  
Comprehensive Analysis ◽  
The Other ◽  
Constant Domain ◽  
Intermolecular Disulfide Bond ◽  
Sds Page

AbstractGenerally, intermolecular disulfide bond contribute to the conformational protein stability. To identify sites where intermolecular disulfide bond can be introduced into the Fab’s constant domain of the therapeutic IgG, Fab mutants were predicted using the MOE software, a molecular simulator, and expressed in Pichia pastoris. SDS-PAGE analysis of the prepared Fab mutants from P. pastoris indicated that among the nine analyzed Fab mutants, the F130C(H):Q124C(L), F174C(H):S176C(L), V177C(H):Q160C(L), F174C(H):S162C(L), F130C(H):S121C(L), and A145C(H):F116C(L) mutants mostly formed intermolecular disulfide bond. All these mutants showed increased thermal stability compared to that of Fab without intermolecular disulfide bond. In the other mutants, the intermolecular disulfide bond could not be completely formed, and the L132C(H):F118C(L) mutant showed only a slight decrease in binding activity and β-helix content, owing to the exertion of adverse intermolecular disulfide bond effects. Thus, our comprehensive analysis reveals that the introduction of intermolecular disulfide bond in the Fab’s constant domain is possible at various locations. These findings provide important insights for accomplishing human Fab stabilization.

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