The primary structure of a rat kappa Bence Jones protein: phylogenetic relationships of V- and C-region genes.

The complete amino acid sequence of a LOU rat k Bence Jones protein, S211, is presented. The availability of such a sequence makes it possible to re-evaluate the phylogenetic relationships of V- and C-region genes. The data suggest that V- and C-genes, and also V-genes between themselves have evolved at different rates. The Vk1-gene seems to have been preserved during evolution and its products could be identified in three other species. The differences between these Vk1 representative sequence are similar and fall inside the range of inter-subgroup differences. On the other hand, the comparison of Ck-regions from four different species agrees with their recognized phylogenetic relationships. Evidence is presented which suggests that two substitutions within the C-region of the S211 k-chain are unrelated to allotypes and presumably represent somatic events or are evidence for multiple isotypes of rat Ck-region.