Brijesh Pandey
Amity University Lucknow, India
Title: Does Zn2+ regulate structure and function of cinnamyl alcohol dehydrogenase isolated from Leucaena leucocephala?
Biography
Biography: Brijesh Pandey
Abstract
Cinnamyl alcohol dehydrogenase (CAD) is a key enzyme of lignin biosynthetic pathway. The effect of Zn2+ on structure and function of native CAD enzyme, isolated from stem xylem of Leucaena leucocephala, was studied. The enzyme exhibited in vitro regulation by Zn2+ concentration. Inactive oligomerization was exhibited by this homodimeric enzyme of 76 kDa, at more than 2 mM Zn2+. Effect of Zn2+ was also studied on recombinant protein. At 2 mM Zn2+, the active enzyme was maximally expressed in soluble fraction and partitioned to inclusion bodies at higher concentrations. The in silico predicted structure revealed presence of two Zn2+ binding domains, one structural and other catalytic. The structural Zn2+ binding (C100,C103,C106,C114) domain was found projected out (as lobe) from main body of enzyme and speculated to cause inactive oligomerization of enzyme at higher Zn2+ concentration. Inactive oligomerization was validated by native PAGE. The structural Zn2+ may thus, be crucial, but the actual role assignment needs further experimental validation by mutagenesis of the structural Zn2+ binding domain. The role validation of structural Zn2+ would enable us to understand the mechanism by which the Zn2+ homoeostasis regulates the enzyme.