Andy Nieuwkoop

Using Solid-state NMR to Study Protein Binding to Phosphatidylinositol Phosphates in Lipid Bilayers

Abstract:

Phosphatidylinositol phosphates (PIPs) are eukaryotic membrane lipids that tightly regulate cellular processes such as cellular growth, metabolism, immunity, and development, through direct interactions with partner proteins. In this work, we seek to directly observe the structure and dynamics of PIP3 in lipid bilayers with and without kindlin-2 (K2), a partner protein activated by PIP3. We probe the effects of the anionic lipid phosphatidylcholine (PS), the divalent cation Ca2+, and cholesterol. We use solution and solid-state 1H, 31P, and 13C NMR combined with MD simulations to characterize the structure and dynamics of PIPs and the binding orientations of the K2 binding domains. Overall, we note the presence of PS restricts the lateral diffusion of PIPs. PIP3, like PS, forms dimers (and larger oligomers) in the presence of Ca2+ which explains differential changes in the rotational dynamics of the PIP headgroup phosphates. The K2 binding domains show numerous contacts with PIP3, many outside of the canonical binding site. The addition of cholesterol modifies the behavior of the lipids by themselves and greatly enhances the sensitivity of NMR experiments on the bound form of K2. 

Speaker: Andy Nieuwkoop, Rutgers University

Andy earned a BA in Chemistry at Carleton College in 2006 and his Ph. D. in Physical Chemistry at the University of Illinois in 2011. His thesis, performed under the direction of Chad Rienstra, was on the use of solid-state NMR to study protein structure. He was an Alexander von Humbolt and Fulbright post-doctoral fellow working with Hartmut Oschkinat at the Leibniz Institute for Molecular Pharmacology in Berlin, Germany where he worked on membrane protein structure and NMR technology development. Since starting his own lab at Rutgers in 2017 he has worked on membranes and lipid-protein interactions as well as material characterization. 

Host: Jeffery Klauda

Seminars start at 4:00 pm, and refreshments will be served at 3:45 pm. All seminars are held in the Conference Room (1116) of the Institute for Physical Science and Technology (IPST) Building (Bldg #085) unless otherwise noted.