Tunable alignment of macromolecules by filamentous phage yields dipolar coupling interactions

Area of Science:

• Structural biology
• Biophysics
• Biochemistry

Background:

• Dipolar coupling interactions offer long-range structural data for macromolecules.
• Previously, obtaining this data required creating an anisotropic environment, limiting its application.
• Macromolecular structure determination in solution has been hindered by the lack of accessible long-range distance and angle information.

Purpose of the Study:

• To introduce a novel method for generating tunable macromolecular alignment in solution.
• To enable the study of dipolar coupling interactions using this new alignment technique.
• To overcome limitations in solution structure determination of macromolecules.

Main Methods:

• Utilized magnetically aligned Pf1 filamentous bacteriophage as a cosolute.
• Developed a phage-induced alignment technique for macromolecules.
• Studied various dipolar coupling interactions (1H-1H, 1H-13C, 1H-15N) in different biomolecules.

Main Results:

• Demonstrated tunable degrees of macromolecular alignment using the phage cosolute.
• Successfully studied dipolar coupling interactions in DNA duplexes, RNA hairpins, and proteins (thioredoxin, apo-calmodulin).
• Showcased the versatility of the method across a wide range of temperatures and solution conditions.

Conclusions:

• The phage-induced alignment technique provides a stable and versatile method for generating partially aligned macromolecules.
• This approach significantly enhances the ability to obtain long-range structural information in solution.
• The method expands the toolkit for macromolecular structure determination, particularly for complex biological systems.