Expression, Purification and Properties of Redox-Sensitive Eye Lens Zeta-Crystallin of Arabian Camel

Title:Expression, Purification and Properties of Redox-Sensitive Eye Lens Zeta-Crystallin of Arabian Camel

Volume: 23 Issue: 6

Author(s): Ajamaluddin Malik, Mohammed Rabbani, Nayyar Rabbani, Abdulrahman M. Al-Senaidy and Mohammad A. Alsenaidy

Affiliation:

Keywords: Aggregation, camel, cataract, eye lens, zeta-crystallin, redox regulated activity.

Abstract: The high protein concentration, unique composition and complex geometry of the lens makes it transparent. α-, β-, and γ-crystallins are present in all the lenses. In addition, taxon-specific crystallins are present in lenses in bulk quantity. Zeta (ζ)-crystallin is an NADPH-dependent quinone oxidoreductase, which constitutes nearly 10 % of the total eye lens protein in the evolutionary divergent animals (Camel, guinea pig and Japanese frog eye lenses) living in different ecological conditions. ζ -Crystallin is also present in human and other animal lenses but at catalytic amount. The physiological role of -crystallin in the eye lens is not well understood, however, truncated ζ-crystallin causes congenital cataract in guinea pig. In earlier study, redox regulated reversible activity of ζ-crystallin was reported. In this study, recombinant camel ζ-crystallin was overexpressed in E.coli and purified to homogeneity. Effect of different concentrations of reducing agent, dithiothretol (DTT) on the quinone oxidoreductase activity of recombinant ζ-crystallin was studied by enzymatic assay. To evaluate the effect of the reducing agent on the ζ-crystallin conformation, we have used far-UV and near-UV CD, intrinsic fluorescence, ANS binding assay and size exclusion chromatography. Our results showed that nearly 50% of the of ζ-crystallin activity was lost at 50 µM DTT. However, no detectable changes in secondary structure were observed. No changes in the tertiary structure and surface hydrophobicity of ζ-crystallin were detected; however, marginal changes were seen at saturating concentration of DTT (1 mM).

Cite this article as:

Malik Ajamaluddin, Rabbani Mohammed, Rabbani Nayyar, M. Al-Senaidy Abdulrahman and A. Alsenaidy Mohammad, Expression, Purification and Properties of Redox-Sensitive Eye Lens Zeta-Crystallin of Arabian Camel, Protein & Peptide Letters 2016; 23 (6) . https://dx.doi.org/10.2174/0929866523666160413140131