scholarly journals Variation in the N-terminal sequence of heavy chains of immunoglobulin G from rabbits of different allotype

1969 ◽  
Vol 112 (2) ◽  
pp. 173-185 ◽  
Author(s):  
J. M. Wilkinson

The sequences of the N-terminal peptides prepared by Pronase digestion of the heavy chain of rabbit immunoglobulin G of allotype Aa1, Aa2 and Aa3 were determined and were shown to be related to the allotype. An N-terminal fragment of about 34 residues was also prepared from the allotype heavy chains, by cleavage with cyanogen bromide; the yield varied with the allotype. The sequences of the cyanogen bromide fragments from the Aa1 and Aa3 heavy chains contain allotype-related variations similar to those found in the N-terminal Pronase peptides, and these sequences are thought to be representative of the whole heavy-chain populations. There is about 60% homology between the two sequences, and superimposed on the differences between them there are a number of positions within each sequence at which at least two amino acids are present.

1968 ◽  
Vol 107 (6) ◽  
pp. 753-763 ◽  
Author(s):  
J. W. Prahl ◽  
R R Porter

The heavy chain of rabbit immunoglobulin G exists in three major allotypic patterns, Aa1–Aa3. A comparison of the amino acid compositions of the heavy chains isolated from immunoglobulin IgG homozygous for each allotypic determinant revealed the presence of an additional methionine residue per chain in the Aa3 allotype relative to the Aa1 and Aa2 allotypes. The position of the additional methionine residue was determined by cyanogen bromide cleavage and by tryptic digestion of the γ-chains; it coincided with the inter-Fd–Fc area of the chain. Isolation and characterization of the corresponding tryptic peptides of 31 amino acid residues from each of the allotypes showed the presence of a methionine-for-threonine replacement in the Aa3 allotype, but only in about 70–80% of the molecules. No other allotypic variations were seen in this tryptic peptide. Allotypically related variations in composition were also detected in the N-terminal cyanogen bromide-cleavage peptide.


1968 ◽  
Vol 107 (6) ◽  
pp. 823-828 ◽  
Author(s):  
Alan R. Williamson ◽  
Brigitte A. Askonas

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.


1971 ◽  
Vol 124 (2) ◽  
pp. 301-318 ◽  
Author(s):  
L. E. Mole ◽  
S. A. Jackson ◽  
R. R. Porter ◽  
J. M. Wilkinson

The sequence has been completed of the N-terminal 94 residues of the variable section of the Fd fragment of heavy chains from rabbit immunoglobulin G (IgG) of allotype As1. Most of the sequence of the same section from IgG of allotype Aa3 is also reported. These results, in conjunction with a substantial sequence of the variable region of allotype Aa2 reported elsewhere (Fleischman, 1971), show the presence of 16 positions (including six consecutive positions) in which the residue present correlates with the allotype. No allotype-related sequence variation has been found in the constant section of the Fd fragment. This evidence supports the view that two genes code for the heavy chain and it can be used as evidence in favour of somatic mutation as the origin of the variability in the sequence of the N-terminal section. The evolutionary origin of the ‘a’ locus allotypes of rabbit immunoglobulins remains obscure.


1970 ◽  
Vol 116 (2) ◽  
pp. 249-259 ◽  
Author(s):  
R. G. Fruchter ◽  
S. A. Jackson ◽  
L. E. Mole ◽  
R. R. Porter

A partial amino acid sequence was given by Cebra, Steiner & Porter (1968b) of the N-terminal half of the heavy chain of rabbit immunoglobulin G. This was extended and in part corrected to give a continuous sequence of 136 residues, which together with other work accounts for three-quarters of the total sequence. Evidence is given suggesting that there is a limited region of 10–15 residues that are exceptionally variable in the heavy chains from pooled rabbit immunoglobulin G.


1969 ◽  
Vol 115 (3) ◽  
pp. 371-375 ◽  
Author(s):  
D. Givol ◽  
E. Hurwitz

Goat immunoglobulin G (IgG) was isolated and characterized. The molecular weights of the IgG and its heavy chains and light chains were found to be 144000, 53600 and 23000 respectively. The light chain corresponds to human L type as was shown by the absence of C-terminal S-carboxymethylcysteine and its high content of N-terminal pyrrolid-2-one-5-carboxylic acid (PCA). The major C-terminal residue of the light chain was serine and the major N-terminal dipeptide was PCA-Ala (0·6mole/mole). The major C-terminal residue of the heavy chain was glycine and the N-terminal sequence of the heavy chain is PCA-Val-Gln. This tripeptide was obtained in a 70% yield.


1967 ◽  
Vol 105 (3) ◽  
pp. 1019-1028 ◽  
Author(s):  
J. W. Prahl

The sequences of the C-terminal octadecapeptides obtained by cyanogen bromide cleavage of the γ-chains of myeloma proteins of the four subclasses, and a urinary heavy-chain-disease protein, have been determined. Although the sequences were markedly homologous, unique replacements were identified that distinguished between the γ2b, γ2c and γ2d subclasses. The data are in accord with the postulated existence of four genetic loci or cistrons, these having arisen by the process of gene duplication.


1968 ◽  
Vol 107 (1) ◽  
pp. 79-88 ◽  
Author(s):  
J. J. Cebra ◽  
L. A. Steiner ◽  
R R Porter

The partial amino acid sequence of two large peptides is described. These were prepared from the N-terminal half of the heavy chain of immunoglobulin G from pooled normal rabbit serum by tryptic digestion after the ∈-amino groups of the lysine residues had been blocked with S-ethyl trifluorothioacetate. These peptides are believed to account for about 145 residues of fragment C-1, the N-terminal section of rabbit immunoglobulin G heavy chain prepared by cyanogen bromide cleavage. The evidence from the present paper and the preceding paper (Cebra, Givol & Porter, 1968) suggests that it may be possible to deduce a predominant amino acid sequence for most, if not all, of this section of the molecule.


1966 ◽  
Vol 100 (2) ◽  
pp. 303-308 ◽  
Author(s):  
JM Wilkinson ◽  
EM Press ◽  
RR Porter

1972 ◽  
Vol 130 (2) ◽  
pp. 539-546 ◽  
Author(s):  
Jean-Claude Jaton ◽  
D. G. Braun

The sequence of the N-terminal 69 residues of heavy chain from a homogeneous rabbit antibody to type III pneumococcal polysaccharide was determined. The sequence is similar to that found in heavy chains of normal pooled rabbit immunoglobulins of the same allotype Aa1. Two regions of the homogeneous heavy chain (residues 35–46 and 62–69) are very similar to corresponding regions of heavy chains from rabbit Aa2 immunoglobulin, as well as from mouse, guinea-pig and human immunoglobulins. In contrast, residues 47–62 appear to be variable. Comparison in this section with another homogeneous anti-pneumococcal antibody (Strosberg et al., 1972) of related specificity and of the same allotype indicates sequence variation in at least three positions. An antibody to group C streptococcal carbohydrate of allotype Aa2 (Fleischman, 1971) differs by five amino acids in the same region of the heavy chain. Sequence variability between these three antibodies does not occur in homologous positions within this variable section. Allotype-related sequences could not be identified in section 34–65.


1970 ◽  
Vol 116 (2) ◽  
pp. 261-268 ◽  
Author(s):  
I. J. O'Donnell ◽  
B. Frangione ◽  
R. R. Porter

Six peptides containing eight half-cystine residues were isolated in good yield, after either oxidation or reduction and carboxymethylation of fragment C-1, which contains the N-terminal half of the heavy chain of rabbit immunoglobulin G. The sequences of five of these peptides had been reported previously (Cebra, Steiner & Porter, 1968b; Wilkinson, 1969) and that of the sixth was established. Other peptides containing half-cystine residues were isolated in much lower yield and are presumed to be derived from minor sequence variants. The cystine-containing peptides from enzymic digests of whole immunoglobulin G and Fc fraction were studied by several techniques and the results obtained enable us to put forward a scheme of the arrangement of the inter- and intra-chain disulphide bonds.


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