Solution NMR backbone resonance assignment of the full-length resistance-related calcium-binding protein Sorcin

Biomol NMR Assign. 2024 Aug 31. doi: 10.1007/s12104-024-10196-0. Online ahead of print.

Abstract

Sorcin is a penta-EF hand calcium-binding protein that confers multidrug resistance in cancer cells. It regulates cellular Ca2+ homeostasis by interacting with calcium channels such as Ryanodine receptor 2 and Sarcoplasmic/endoplasmic reticulum Ca2+-ATPase in a calcium-dependent manner. The crystal structure of the Sorcin has been determined in both calcium-free and calcium-bound states to understand calcium-binding induced conformational change. However, due to its flexibility, most of the N-terminal domain is invisible in these crystal structures. Here we report the 1H, 13C, and 15N backbone resonance assignments of full-length Sorcin in the calcium-free state using solution NMR. The protein secondary structure was predicted based on the assigned backbone chemical shifts using TALOS+ and CSI 3.0. Our backbone resonance assignment of the full-length Sorcin provides a foundation for future NMR spectroscopic studies to uncover the mechanism of Ca2+ sensing by Sorcin.