κ Chain variable regions from three galactan binding myeloma proteins

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Abstract
A series of 7 BALB/c [mouse] myeloma proteins was identified with binding specificity for antigens containing .beta.(1 .fwdarw. 6)-D-galactopyranosyl moieties. The primary amino acid sequence of the first 108 residues from the L chains of 3 of these proteins was determined. The framework portions of the variable regions of these 3 L chains are identical except for residue 100 at which position 3 different amino acids are found in the 3 chains. An additional interchange was found at position 106 in 1 of the proteins. Based on recent DNA sequence studies suggesting that the variable region ends at residue 97, these substitutions indicate the possible excistence of multiple genes coding for the region beginning at residue 98 and continuing toward the carboxy terminus. A single amino acid interchange was observed in complementarity determining regions occurring in L3. This substitution (Ile-Trp) would require changes in all 3 codon bases to produce the respective amino acids if 1 were derived from the other. Two of these chains are thus indistinguishable for their first 100 amino acids and are the 1st pair of .kappa. chains to exhibit complete identity over their variable regions.