A Comparative Study of β-Crystallins from Ungulates, Whale and Dog

Abstract

The major β-crystallins from the ocular lens of 4 species from the order Artiodactyla (calf, sheep, hog and goat) and 3 perissodactyls (rhino, tapir and donkey) were isolated and compared by means of gel electrophoretic techniques and immunodiffusion. In addition β-crystallins from whale and dog were used in this study. Although these β-crystallins were not identical, a high degree of similarity was found between animals of the same order. Furthermore all species studied seem, like previously found in calf, to have one major component (βBp) with identical electrophoretic properties, which is shared by both β_H(_igh)-crystallin and β_L(ow)- Crystallin. This suggests a conservative character of this polypeptide in evolution. The most striking differences between artiodactyls and perissodactyls are found in the β_H-aggregates, especially apparent is the occurrence of the polypeptide, designated as βB1 in the calf, in the investigated artiodactyl species, but not in the perissodactyls. This result is sustained by immunodiffusion studies. Moreover these latter experiments also indicate that in whale and dog a polypeptide occurs, which is immunologically related to βB1 from calf. The results may be explained by the loss or profound structural change of this polypeptide in the course of perissodactyl evolution