Expression and purification of his-tagged recombinant mouse ζ-crystallin

ζ-Crystallin is an NADPH-binding protein consisting of four identical 35 kD subunits. The protein possesses quinone oxidoreductase activity, and is present in large amounts in the lenses of camelids, certain hystricomorphic rodents, and the Japanese tree frog, and in lower catalytic amounts in certain tissues of various species. In this study, recombinant methods were used to produce substantial quantities of his-tagged recombinant mouse ζ-crystallin, which was then purified to homogeneity. The yield of pure recombinant mouse ζ-crystallin was five times that obtained previously for purification of recombinant guinea pig ζ-crystallin. The quinone oxidoreductase activity of purified his-tagged recombinant mouse ζ-crystallin was comparable to that of purified native guinea pig lens ζ-crystallin, and to that previously reported for recombinant guinea pig ζ-crystallin. The method permits production of substantial amounts of recombinant ζ-crystallin for conducting studies on the biological role of this interesting protein, which exists in such high concentration in the lenses of certain species.