Adaptive Multi-Layer Simulations of NarK Transport Protein

University Of Colorado At Denver-Downtown Campus, Denver CO

Investigators

Abstract

With funding from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry, Hai Lin and Emilie Guidez of the University of Colorado-Denver will develop and apply novel computational algorithms to study how ions are transported through the membrane protein NarK. The NarK protein imports nitrate (a mineral form of the essential element nitrogen) into the cell and exports nitrite (a metabolite that can be toxic in high concentrations) out of the cell. However, the mechanism of the NarK protein remains poorly understood. Accurate and efficient computer modeling and simulations are highly desired to provide critical insights. Lin and Guidez will formulate new multiscale algorithms that seamlessly combine quantum and classical modeling techniques, and employing these algorithms, their research groups will set forth to unearth the atomistic details on how NarK helps the ions travel across the cell membranes. This collaborative research has the potential to fundamentally advance understanding of nutrient uptake by membrane transporters and, consequently, in the longer term, potentially assist in the development of novel therapies for diseases related to these protein malfunctions. The University of Colorado-Denver is both a Hispanic-Serving Institution (HSI) and an Asian American Native American Pacific Islander-Serving Institution. Lin and Guidez will actively recruit students from underrepresented groups to promote diversity, both directly and through the EUReCA! and XSEDE EMPOWER programs. In addition, they will expand the highly successful partnership with Cherry Creek High School to include Cherry Creek Innovation Campus, where high-school teachers will participate in hands-on research through a yearly summer research program. These outreach activities will promote K-12 curriculum innovation and explore students to the excitement of research in STEM (science, technology, engineering and mathematics) fields. The operation mechanism of the NarK transporter has remained elusive for many years. For example, mutagenesis experiments have revealed that the binding-site residues with delocalized pi bonds are essential to the transport activities, but exactly how they influence substrate recruitment and translocation remains unknown. Lin and Guidez will develop novel adaptive-partitioning multi-layer methods that are next-generation ONIOM-like methods with on-the-fly relocated interlayer boundaries. The new algorithms are expected to enable highly accurate and efficient dynamics simulations to unlock the molecular details of anion binding and translocation in NarK. Both the new simulation tools and the mechanistic insights resulting from this project can potentially transform the study of ion migration for many channels and transporters. Through a series of summer outreach programs, this project will provide excellent opportunities to get K-12 teachers and students by exposing them to modern computer modeling techniques, and actively engaging them in biochemical research. 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.