A Simple, Robust Biomimetic Charge Separation Protein Domain

Cuny City College, New York NY

Investigators

Abstract

Intellectual Merit This research concerns the design, synthesis and analysis of an artificial protein which will have the ability to create a relatively long-lived charge separated state when excited with short bursts of light. The process of charge separation is the first, most important step in photosynthesis, and this construction will allow researchers to examine the underlying physical processes which support charge separation. The project involves the design of a three cofactor helical bundle protein domain which binds its cofactors by three orthogonal mechanisms: the primary donor molecule will be a zinc(II)-phthalocyanine which binds specifically to mono-histidine pentacoordinate sites. The acceptor cofactor binding site will be a hexacoordinate bis-histidine site which tightly and stably binds a variety of iron-containing macrocycles. The donor site will contain a C-type heme covalently attached in vivo using the cytochrome C biogenesis system. This charge separation domain will be covalently attached to the flavoprotein reductase domain of phthalate dioxygenase reductase, enabling the donor to be poised for electron transfer to the primary donor phthalocyanine cofactor via the natural protein chimera by the simple addition of NADH. The intended final product will be a simple, robust modular protein domain which will serve many different scientists and engineers in their creation of solar energy-driven devices. Broader Impact This work will not only improve the understanding of the engineering of charge separation, it will result in a series of protein domains with tunable kinetics and energetics which can be used in the creation of light-activated nanodevices. CCNY, a public, city university, has an extremely diverse multi-ethnic student body. An educational plan, which introduces undergraduates, graduate students and New York City Public High School teachers to the interdisciplinary science of biophysics, will be developed.