Intellectual Merit: 

From selective binding of metal ions for controlling gene transcription to the reduction of O₂ for driving aerobic respiration, metalloproteins carry out many cellular functions that are central to biology. The understanding of how metalloproteins function has grown immensely thanks to advances in structure determination methods, spectroscopy, bioanalytical chemistry and computation, as well as through studies of biomimetic inorganic complexes. Yet, the ability to replicate or improve upon the structures and functions of metalloproteins by de novodesign has remained at an elementary level. Similarly, there is little insight on how complex bioinorganic functions may have emerged on simple peptide/protein scaffolds during natural evolution. Toward addressing the gaps in the understanding of the interplay between protein structure/dynamics and metal coordination/reactivity, Prof. Akif Tezcan and his group have pursued a bottom-up design strategy in which active metal sites are built in nascent interfaces between protein building blocks. Toward this goal, the group has developed new chemical design strategies based on the use of metal coordination and disulfide bonding interactions for the assembly of supramolecular protein architectures and their utilization as platforms for engineering new metal-based functions, with some of the highlights including:

- the de novo design of allosteric protein assemblies in which the binding and dissociation of Zn²⁺ ions are remotely coupled to the formation and breakage of a disulfide bond over large distances;

-the design and construction of artificial metalloenzymes capable of ester and beta-lactam hydrolysis in vivo (and in vitro), whose examination led to new insights into the importance of protein flexibility/rigidity in the design and evolution of catalytic functions:

- the development of a new metalloprotein design approach (Metal Active Sites through Covalent Tethering, MASCoT), which enables the straightforward construction of metal-based active sites in disulfide-mediated protein-protein interfaces.

Broader Impacts:

This research project entailed a highly multidisciplinary approach that combined the principles of synthetic inorganic chemistry, rational protein design and in vivo evolution in unique ways to engineer and evolve new metal-based functionalities in biological platforms. Such an ability to construct complex biological structures with tunable metal sites–and integrating it with the evolvability of a living system–has not only provided fundamental insights into biological self-assembly processes, metal-protein interactions and bioinorganic reactivity, but also lent access to novel functionalities and reactivities, with potential impact on diverse research areas as inorganic chemistry, protein evolution and engineering, biological self-assembly, and biomaterials. In line with its multidisciplinary nature, the proposed project has enabled the research efforts a diverse group of postdocs, graduate, and undergraduate students and provided them with valuable experimental skills in coordination chemistry, molecular biology, in-lab evolution, protein biochemistry, chemical synthesis, spectroscopic techniques and crystallography. In addition, the grant has supported extensive outreach efforts including active recruitment of members of underrepresented groups for research, recruitment of high school students through various self-initiated and campus-supported programs, and participation in local science fairs.

Last Modified: 12/03/2021
Modified by: Faik A Tezcan