scholarly journals Interchain disulphide-bond formation in the assembly of immunoglobulin G. Heavy-chain dimer as an intermediate

1968 ◽  
Vol 109 (4) ◽  
pp. 637-643 ◽  
Author(s):  
Brigitte A. Askonas ◽  
Alan R. Williamson
Keyword(s):  
Heavy Chain ◽  
Light Chain ◽  
Immunoglobulin G ◽  
Bond Formation ◽  
Disulphide Bond ◽  
Pulse Labelling ◽  
Myeloma Protein ◽  
Chain Dimer ◽  
Disulphide Bond Formation ◽  
Covalently Linked

1. The role of disulphide-bond formation in the assembly of G2a myeloma protein 5563 was studied by pulse-labelling ascitic plasma cells of tumour-line 5563 for 2–8min. with radioactive amino acids, and analysing the intracellular proteins. Myeloma-protein determinants were first purified by ion-exchange chromatography under conditions that do not dissociate non-covalently linked sub-units of immunoglobulin G. The pulse-labelled material was then analysed by electrophoresis on polyacrylamide gels in sodium dodecyl sulphate–phosphate–urea buffer, which dissociates non-covalently linked sub-units; after gel electrophoresis, radioactive protein bands were located by radioautography, and characterized immunologically after elution. 2. Two heavy-chain intermediates were detected: (i) heavy-chain dimer; (ii) the dimer with one light chain attached. Free light chains had previously been shown to be intermediates in assembly. No evidence for the presence of half-molecules (one light chain attached to one heavy chain) was obtained. The formation of the disulphide bond between the heavy chains thus appears to precede the light-chain–heavy-chain linkage in immunoglobulin G assembly.

Vibrio spp. secrete proaerolysin as a folded dimer without the need for disulphide bond formation

1995 ◽  
Vol 17 (6) ◽  
pp. 1035-1044 ◽  
Author(s):  
Kim R. Hardie ◽  
Angela Schulze ◽  
Michael W. Parker ◽  
J. Thomas Buckley
Keyword(s):  
Bond Formation ◽  
Disulphide Bond ◽  
Disulphide Bond Formation ◽  
Vibrio Spp

scholarly journals Differential reduction of interchain disulphide bonds of mouse immunoglobulin G

1968 ◽  
Vol 107 (6) ◽  
pp. 823-828 ◽  
Author(s):  
Alan R. Williamson ◽  
Brigitte A. Askonas
Keyword(s):  
Heavy Chain ◽  
Immunoglobulin G ◽  
Polyacrylamide Gel Electrophoresis ◽  
Partial Reduction ◽  
Free Light Chains ◽  
Myeloma Protein ◽  
Heavy Chains ◽  
Disulphide Bonds ◽  
Rabbit Immunoglobulin ◽  
Mouse Immunoglobulin

The relative lability of the interchain disulphide bonds of mouse G2a-myeloma protein 5563 was studied as a function of 2-mercaptoethanol concentration. Analysis of partial-reduction mixtures by polyacrylamide-gel electrophoresis and microdensitometry showed that the disulphide bonds between light and heavy chains are much more susceptible to reduction than the bonds between heavy chains. At a low concentration of 2-mercaptoethanol (10mm) the major dissociable products of mouse immunoglobulin G are heavy-chain dimers and free light chains. These findings contrast with the reported behaviour of rabbit immunoglobulin G, for which the lability of inter-heavy-chain bonds was found to exceed that of the bonds linking light and heavy chains (Hong & Nisonoff, 1965); the relative stability of rabbit immunoglobulin G interchain bonds was confirmed in the present study. Examination of human immunoglobulin G and an immunoglobulin G (γ2) of guinea pig showed that at least in the majority of molecules, as with mouse immunoglobulin G, the disulphide bonds between light and heavy chains are more susceptible to reduction than the inter-heavy-chain bonds.

Biosynthesis of immunoglobulins on polyribosomes and assembly of the IgG molecule

1966 ◽  
Vol 166 (1003) ◽  
pp. 232-243 ◽  
Keyword(s):  
Light Chain ◽  
Gradient Centrifugation ◽  
Intermediate Stage ◽  
Light Chains ◽  
Pulse Labelling ◽  
Myeloma Protein ◽  
Heavy Chains ◽  
Specific Antisera ◽  
Independent Synthesis ◽  
Small Pool

Immunoglobulin G formation was studied using as model system an ascitic form of the murine plasmacytom 5563. Following pulse labelling of the cells with 3 H-leucine, polyribosomes were fractionated on sucrose gradients. By the use of antisera specific for various parts of the IgG molecule, nascent heavy and light chains were detected on distinct polyribosomes of different size. Polyribosomes carrying heavy chain determinants were present in clusters with maximum sedimentation constants of around 300 S.; a much lower proportion of radioactivity was detectable as light chain determinants on polyribosomes up to 200 S. This observation is consistent with the independent synthesis of each chain as one polypeptide unit. Release of light chains appears to be an intermediate stage in the assembly of the IgG molecule. After pulse labelling of cells soluble IgG determinants were analysed by sucrose gradient centrifugation and precipitation with specific antisera. Only the light chains were released into a small pool which may control the release of heavy chains from polyribosomes. The radioactivity of the light chain pool reached a maximum at 10 min, whereas that of whole myeloma protein increased linearly with time. These results fit the interpretation that light chains form a small, rapidly turning over, pool before being incorporated into whole IgG molecules.

scholarly journals Influence of the peptide-chain length on disulphide-bond formation in neurohypophysial hormones and analogues

1978 ◽  
Vol 173 (2) ◽  
pp. 403-409 ◽  
Author(s):  
G Moore
Keyword(s):  
Acetic Acid ◽  
Arginine Vasopressin ◽  
Solid Phase ◽  
Bond Formation ◽  
Gel Filtration ◽  
Arginine Vasotocin ◽  
Disulphide Bond ◽  
Peptide Chain ◽  
Phase Method ◽  
Disulphide Bond Formation

(8-Arginine)vasopressin, (8-arginine)vasotocin, oxytocin and oxypressin, the ‘ring’ derivatives pressinamide and tocinamide, and the extended-chain analogues Pro-Arg-Val-(8-arginine)vasopressin and (8-arginine)vasopressinoyl-Ala-Met-Ala-NH(2), were synthesized by the solid-phase method and purified by sequential gel filtration on Sephadex G-15 in 50% acetic acid and 0.2M-acetic acid. Controlled oxidation of the thiol groups of the reduced peptides obtained after deprotection with sodium in liquid ammonia gave rise to products that depended on the length of the peptide chain: (i) nonapeptides gave monomer and dimer species, (ii) hexapeptides produced mixtures containing higher polymers, and (iii) dodecapeptides gave predominantly monomer with some dimerized material. The evidence suggests that the presence of the acyclic tail tripeptide in the nonapeptide hormones induces a conformation in the preceding hexapeptide that favours the formation of an intramolecular disulphide bond. For (8-arginine)vasopressin, intramolecular disulphide-bond formation is enhanced by extension of the peptide chain from either the N- or the C-terminus. The possible significance of these studies to neurohypophysial hormone-prohormone relationships is discussed.

Crystal structure of the DsbA protein required for disulphide bond formation in vivo

Nature ◽  
1993 ◽  
Vol 365 (6445) ◽  
pp. 464-468 ◽  
Author(s):  
Jennifer L. Martin ◽  
James C. A. Bardwell ◽  
John Kuriyan
Keyword(s):  
Crystal Structure ◽  
Bond Formation ◽  
Disulphide Bond ◽  
Disulphide Bond Formation
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