High Affinity Electrostatic Interactions Support the Formation of CdS Quantum Dot:Nitrogenase MoFe Protein Complexes

• Published in: Nano letters 2023-11, Vol.23 (22), p.10466-10472
• Main Authors: Pellows, Lauren M., Willis, Mark A., Ruzicka, Jesse L., Jagilinki, Bhanu P., Mulder, David W., Yang, Zhi-Yong, Seefeldt, Lance C., King, Paul W., Dukovic, Gordana, Peters, John W.
• Format: Article
• Language: English
• Subjects: CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; electron transfer; microscope thermophoresis; NANOSCIENCE AND NANOTECHNOLOGY; nitrogen reduction; nitrogenase; photocatalysis; quantum dots
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.3c03205

Nitrogenase MoFe protein can be coupled with CdS nanocrystals (NCs) to enable photocatalytic N2 reduction. The nature of interactions that support complex formation is of paramount importance in intermolecular electron transfer that supports catalysis. In this work we have employed microscale thermophoresis to examine binding interactions between 3-mercaptopropionate capped CdS quantum dots (QDs) and MoFe protein over a range of QD diameters (3.4-4.3 nm). The results indicate that the interactions are largely electrostatic, with the strength of interactions similar to that observed for the physiological electron donor. In addition, the strength of interactions is sensitive to the QD diameter, and the binding interactions are significantly stronger for QDs with smaller diameters. The ability to quantitatively assess NC protein interactions in biohybrid systems supports strategies for understanding properties and reaction parameters that are important for obtaining optimal rates of catalysis in biohybrid systems.