Utilization of lysine ¹³C-methylation NMR for protein-protein interaction studies.

Yoshikazu Hattori, Kyoko Furuita, Izuru Ohki, Takahisa Ikegami, Harumi Fukada, Masahiro Shirakawa, Toshimichi Fujiwara, Chojiro Kojima

Journal of biomolecular NMR 2013 Jan

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Chemical modification is an easy way for stable isotope labeling of non-labeled proteins. The reductive (13)C-methylation of the amino group of the lysine side-chain by (13)C-formaldehyde is a post-modification and is applicable to most proteins since this chemical modification specifically and quickly proceeds under mild conditions such as 4 °C, pH 6.8, overnight. (13)C-methylation has been used for NMR to study the interactions between the methylated proteins and various molecules, such as small ligands, nucleic acids and peptides. Here we applied lysine (13)C-methylation NMR to monitor protein-protein interactions. The affinity and the intermolecular interaction sites of methylated ubiquitin with three ubiquitin-interacting proteins were successfully determined using chemical-shift perturbation experiments via the (1)H-(13)C HSQC spectra of the (13)C-methylated-lysine methyl groups. The lysine (13)C-methylation NMR results also emphasized the importance of the usage of side-chain signals to monitor the intermolecular interaction sites, and was applicable to studying samples with concentrations in the low sub-micromolar range.

Citation

Yoshikazu Hattori, Kyoko Furuita, Izuru Ohki, Takahisa Ikegami, Harumi Fukada, Masahiro Shirakawa, Toshimichi Fujiwara, Chojiro Kojima. Utilization of lysine ¹³C-methylation NMR for protein-protein interaction studies. Journal of biomolecular NMR. 2013 Jan;55(1):19-31