77Se-13C based dipolar correlation experiments to map selenium sites in microcrystalline proteins

Author:

Quinn, Caitlin M

Xu, Shiping

Hou, Guangjin

Chen, Qingqing

Sail, Deepak

Byrd,Robert

Rozovsky, Sharon [ORCID]
Author Address

Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA., State Key Laboratory of Catalysis, National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, 116023, China., Chemistry and Synthesis Center, National Heart Lung and Blood Institute, Bethesda, MD, USA., Center for Cancer Research, National Cancer Institute, Frederick, MD, USA., Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, USA. rozovsky@udel.edu.,

Abstract:

Sulfur-containing sites in proteins are of great importance for both protein structure and function, including enzymatic catalysis, signaling pathways, and recognition of ligands and protein partners. Selenium-77 is an NMR active spin-1/2 nucleus that shares many physiochemical properties with sulfur and can be readily introduced into proteins at sulfur sites without significant perturbations to the protein structure. The sulfur-containing amino acid methionine is commonly found at protein-protein or protein-ligand binding sites. Its selenium-containing counterpart, selenomethionine, has a broad chemical shift dispersion useful for NMR-based studies of complex systems. Methods such as (1H)-77Se-13C double cross polarization or {77Se}-13C REDOR could be valuable to map the local environment around selenium sites in proteins but have not been demonstrated to date. In this work, we explore these dipolar transfer mechanisms for structural characterization of the GB1 V39SeM variant of the model protein GB1 and demonstrate that 77Se-13C based correlations can be used to map the local environment around selenium sites in proteins. We have found that the general detection limit is?~?5 Å, but longer range distances up to?~?7 Å can be observed as well. This study establishes a framework for the future characterization of selenium sites at protein-protein or protein-ligand binding interfaces. © 2022. The Author(s), under exclusive licence to Springer Nature B.V.

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