Fast NMR method to probe solvent accessibility and disordered regions in proteins

Area of Science:

• Biochemistry
• Structural Biology
• Biophysics

Background:

• Protein structure and dynamics are vital for cellular processes and disease mechanisms.
• Intrinsically disordered protein (IDP) regions exhibit multifunctionality through transient conformations, posing challenges for traditional study methods.
• IDPs are abundant in small viruses, enabling diverse functions from limited proteomes.

Purpose of the Study:

• To develop a straightforward Nuclear Magnetic Resonance (NMR) method for differentiating solvent accessibility in structured and IDP regions.
• To characterize the flexible fold region of the dengue virus (DENV) capsid (C) protein.
• To provide a rapid and easily interpretable method for IDP characterization.

Main Methods:

• Utilized a straightforward NMR technique based on minimal pH changes.
• Employed the well-established 1H-15N HSQC pulse sequence.
• Applied the method to the dengue virus (DENV) capsid (C) protein and streptococcal protein G.

Main Results:

• Successfully differentiated the solvent accessibility of single amino acid N-H groups in structured versus IDP regions.
• Gained insights into the biological activity of the DENV C flexible fold region.
• Demonstrated the method's simplicity, speed, and ease of interpretation.

Conclusions:

• The described NMR method is a rapid and useful first-choice approach for IDP characterization.
• This technique facilitates the study of protein structure and dynamics in IDPs, advancing basic and applied research.
• The method is easily implementable in standard protein NMR workflows.