¹H, ¹³C and ¹⁵N resonance assignment for the human K-Ras at physiological pH

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• K-Ras is a small GTPase crucial for cell signaling, frequently mutated in various cancers.
• Ras protein activity relies on GTP/GDP binding, regulated by effector proteins.
• Previously, NMR signals from key Ras effector-binding regions were unassigned due to protein dynamics.

Purpose of the Study:

• To obtain complete NMR assignments for human K-Ras (residues 1-166) in its GDP-bound form.
• To enable detailed monitoring of the Ras functional cycle and its interactions.
• To facilitate the study of Ras mutations in cancer.

Main Methods:

• Nuclear Magnetic Resonance (NMR) spectroscopy was employed.
• Complete backbone and C(β) assignments were achieved.
• Partial H(α), H(β), and C(γ) assignments were obtained for human K-Ras (1-166) at pH 7.4.

Main Results:

• Complete backbone and C(β) NMR assignments for GDP-bound human K-Ras (1-166) were successfully determined.
• Partial assignments for H(α), H(β), and C(γ) resonances were also achieved.
• These assignments cover functionally important regions of the protein.

Conclusions:

• The reported NMR assignments provide a foundation for detailed functional studies of K-Ras.
• This work allows for the observation of previously unobservable signals from Ras effector-binding regions.
• Enables comprehensive monitoring of Ras interactions with nucleotides and effector proteins, crucial for cancer research.