Structural delineation of stem-loop RNA binding by human TAF15 protein

Area of Science:

• Molecular Biology
• Structural Biology
• Biochemistry

Background:

• The FET (FUS, EWS, TAF15) protein family, including TAF15 and FUS, are crucial nucleic acid binding proteins involved in RNA processing and transport.
• Understanding the structural basis of RNA recognition by FET proteins is essential for elucidating their diverse cellular functions.

Purpose of the Study:

• To elucidate the molecular mechanism by which the TAF15 RNA Recognition Motif (RRM) binds to RNA targets.
• To provide a structural basis for RNA recognition and discrimination within the FET protein family.

Main Methods:

• Solution-state Nuclear Magnetic Resonance (NMR) spectroscopy to determine the TAF15-RRM structure and RNA binding interactions.
• Isothermal titration calorimetry (ITC) to quantify binding affinities.
• Molecular docking and dynamics simulations to model protein-RNA interactions.

Main Results:

• The TAF15-RRM employs a non-canonical RNA recognition mode, distinct from classical base-stacking interactions.
• RNA binding is primarily mediated by a hydrogen bonding network between RNA bases and a concave surface on the TAF15-RRM.
• Binding affinity is dependent on the structural features of the RNA, rather than its specific sequence.

Conclusions:

• TAF15-RRM-RNA interactions are governed by hydrogen bonds and structural complementarity, offering a new paradigm for FET protein-RNA binding.
• This study provides critical insights into the structural mechanisms of nucleic acid recognition by the FET protein family.