Our work on aqueous metal quantum dot biosynthesis was just published online in International Journal of Biological Macromolecules.
January 20, 2021
The development and utilization of inorganic material biosynthesis have evolved into single macromolecular systems. A putative cystathionine γ-lyase of bacteria Stenotrophomonas maltophilia (smCSE) is a newly identified biomolecule that enables the synthesis of nanomaterials. Due to the lack of structural information, the mecha- nism of smCSE biosynthesis remains unclear. Herein, we obtain two atomic-resolution smCSE-form X-ray structures and confirm that the conformational changes of Tyr108 and Lys206 within the enzyme active sites are critical for the protein-driven synthesis of metal sulfide quantum dots (QDs). The structural stability of tetramer and the specificity of surface amino acids are the basis for smCSE to synthesize quantum dots. The size of QD productscanberegulatedbypredesignedaminoacidsandthemorphologycanbecontrolledthroughproteolytic treatments. The growth rate is enhanced by the stabilization of a flexible loop in the active site, as shown by the X-ray structure of the engineered protein which fused with a dodecapeptide. We further prove that the smCSE- driven route can be applied to the general synthesis of other metal sulfide nanoparticles. These results provide a better understanding of the mechanism of QD biosynthesis and a new perspective on the control of this biosyn- thesis by protein modification.
