Metal-reducing enzymatic tag for optical and electron microscopy

Abstract

Enzymes that reduce specific metal or metalloid ions to insoluble form are important to science. Peptides isolated from yeast- and phage-display libraries can affect the size and morphology of inorganic materials during their synthesis. Herein, an Se binding peptide was fused to an enzyme capable of reducing selenite (SeO) to a Senanoparticle (SeNP). The fusion of the Se binding peptide to the metalloid reductase provided size control of the resulting SeNP. The SeNP product also remains associated to the enzyme fusion. The Se binding peptide fusion to the enzyme increases the enzyme's SeOreductase activity. Modification of enzyme activity was absent, and the size control of particles was diminished when the Se binding peptide was added exogenously to the reaction mixture. Binding of the peptide is attributed to His based ligation that results in a conformational change to the peptide.