NSF-BSF: Unraveling the molecular determinants of protein oligomerization

The complexity of life is predicated on the ability of biomolecules to organize themselves into higher-order functional structures. This project will investigate how evolutionary processes shape the ability of individual proteins to self-assemble into complex structures that then generate new biomolecular functionalities than possible for the individual proteins themselves.

Insights gained from this research will be useful for protein engineering attempts to create de novo or expanded functionalities of enzymes and other structural proteins. The project will also provide support and resources for K-12 teachers to enhance STEM participation in a socioeconomically challenged section of Atlanta (Clayton Co.). We anticipate that stronger research literacy at the teacher level will generate greater interest and participation of K-12 students in STEM activities such as science fairs, resulting in better preparation for post-secondary education.

This project will specifically focus on methionine S-adenosyltransferases (MATs), an essential homo-tetrameric enzyme of central metabolism characterized by high variability in quaternary structure integrity among its homologs. The research will assess thermodynamics and kinetics of MAT folding and (dis)assembly, folding dependency of individual MAT subunits on molecular chaperones, aggregation propensity of intermediate MAT sub-complexes, and the intracellular turnover and activity of assembled MAT complexes.

Comparative analysis of extant sequences will be complemented with ancestral sequence reconstruction of the intermediate steps linking ancestral and derived states. The project will generate bacterial strains in which genes encoding the endogenous MAT homomers are replaced with extant or ancestrally reconstructed orthologs, subject the strains to laboratory evolution in a variety of environmental conditions, and identify the genetic, structural, functional and systems determinants of adaptation as best possible given the constraints of laboratory evolution.

Through this multifaceted approach, the project will enable a genotype-phenotype-fitness connection for homomer evolution.

This project is jointly funded by the Genetic Mechanisms an.d Molecular Biophysics programs of the Molecular and Cellular Biosciences Division in the Biological Sciences Directorate.

This collaborative US/Israel project is supported by the US National Science Foundation and the Israeli Binational Science Foundation.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.