The acidic domain is a unique structural feature of the splicing factor SYNCRIP

Area of Science:

• Molecular Biology
• Structural Biology
• Biochemistry

Background:

• The splicing factor SYNCRIP (hnRNP Q) plays roles in viral replication, neural development, circadian rhythms, and APOBEC1 regulation.
• SYNCRIP contains RNA-recognition motifs (RRMs), an N-terminal acidic-rich domain (AcD12-97), and a C-terminal RGG/RXG box.
• The N-terminal acidic-rich segment is crucial for interactions with APOBEC1.

Purpose of the Study:

• To determine the structure of the N-terminal acidic-rich domain of SYNCRIP.
• To investigate the structural characteristics and potential interaction sites of this domain.

Main Methods:

• Structure-based annotation and domain identification.
• Nuclear Magnetic Resonance (NMR) spectroscopy to determine the 3D structure of the identified domain.

Main Results:

• The N-terminal region AcD12-97 does not form a globular domain as previously thought.
• A self-folding globular domain, AcD24-107, with an all α-helix architecture was identified within this region.
• The NMR structure of AcD24-107 revealed a distinct architecture compared to prior models, featuring charged surfaces and a hydrophobic cavity.

Conclusions:

• The SYNCRIP N-terminal domain AcD24-107 possesses a unique all α-helix structure.
• This domain contains potential interaction surfaces, including charged areas and a hydrophobic cavity, suggesting roles in protein-protein or protein-nucleic acid interactions.