Solid-state NMR is a powerful tool for studying membrane protein structures, but high spectral resolution is often hindered by 13 C coupling effects. To that end, researchers from East China University of Science and Technology and Peking University have now introduced a simple and cost-effective labeling method that overcomes this challenge.
For the study, the team used Pichia pastoris ( P . pastoris ), a yeast that can grow on methanol as its only carbon source. “By mixing natural abundance methanol with carbon-13-labeled methanol in the culture medium, we achieved random fractional labeling of a eukaryotic membrane protein—a rhodopsin from Leptosphaeria maculans (LR). This approach reduces carbon-carbon coupling, sharpening spectral peaks and improving resolution,” shares Shenlin Wang, the study’s corresponding author and a professor at East China University of Science and Technology.
“What's exciting is that we can now obtain high-resolution NMR spectra using only inexpensive 13 C methanol,” adds Wang. “This method is particularly useful for researchers who need to assess protein quality or study site-specific dynamics without the high costs of specialized labeled precursors.”
Notably, the researchers The found that a 25% 13 C enrichment level offered the best balance between resolution and signal sensitivity, cutting average 13 C linewidths by half compared to fully labeled proteins. This led to a 50% increase in well-resolved peaks in key NMR spectra. Importantly, the spectral quality matched that achieved with far more expensive 2- 13 C glycerol labeling—but at about one-tenth of the cost.
“This labeling strategy is expected to facilitate structural, dynamic, and interaction studies of eukaryotic membrane proteins, which are crucial for understanding many biological processes and drug targets,” Wang says.
###
Contact the author: Shenlin Wang, East China University of Science and Technology, wangshenlin@ecust.edu.cn
The publisher KeAi was established by Elsevier and China Science Publishing & Media Ltd to unfold quality research globally. In 2013, our focus shifted to open access publishing. We now proudly publish more than 200 world-class, open access, English language journals, spanning all scientific disciplines. Many of these are titles we publish in partnership with prestigious societies and academic institutions, such as the National Natural Science Foundation of China (NSFC).
Magnetic Resonance Letters
Experimental study
Lab-produced tissue samples
A random fractional¹³C labeling strategy for P. pastoris expressed eukaryotic membrane proteins for solid-state NMR studies
The authors declare no competing interests.