Cold-Shock Domains-Abundance, Structure, Properties, and Nucleic-Acid Binding

Area of Science:

• Molecular Biology
• Biochemistry
• Genetics

Background:

• The cold-shock domain is a conserved protein structure found in all kingdoms of life.
• It is present in bacterial cold-shock proteins and human proteins, often associated with unfolded regions.
• Cold-shock proteins can be induced by cold shock, particularly in bacteria.

Purpose of the Study:

• To elucidate the structure-function relationship of the cold-shock domain.
• To explain the nucleic acid binding capabilities and sequence selectivity of cold-shock domains.
• To provide a rationale for the diverse biological functions of cold-shock domain-containing proteins.

Main Methods:

• Structural analysis of the five-stranded antiparallel β-barrel structure.
• Identification of conserved nucleic acid binding surfaces.
• Analysis of binding interactions, including stacking interactions between nucleobases and aromatic sidechains.

Main Results:

• Cold-shock domains possess a conserved five-stranded antiparallel β-barrel structure.
• A conserved surface facilitates binding to single-stranded nucleic acids (DNA and RNA).
• Binding is primarily mediated by stacking interactions, leading to limited sequence selectivity.

Conclusions:

• The conserved structure and binding mode explain the promiscuous DNA/RNA binding of cold-shock domains.
• This binding capability underpins their roles in transcription regulation, DNA repair, splicing, translation, and RNA sequestration.
• The cold-shock domain's simple architecture supports a complex and vital biology.