Affinity separation of polyribonucleotide-binding human blood proteins

Area of Science:

• Biochemistry
• Molecular Biology
• Proteomics

Background:

• Blood plasma contains numerous proteins with diverse functions.
• Nucleic acid-binding proteins play critical roles in cellular processes.
• Understanding protein-nucleic acid interactions is essential for biological research.

Purpose of the Study:

• To identify and characterize polyribonucleotide-binding proteins in human blood plasma.
• To investigate the binding preferences of specific plasma proteins to different RNA sequences.
• To explore the effect of glycation on albumin's RNA-binding properties.

Main Methods:

• Affinity chromatography using immobilized homopolyribonucleotides (poly(A), poly(G), poly(U), poly(C)) and duplexes.
• Protein capture and identification using immobilized nucleic acid ligands.
• Analysis of protein-ligand interactions, including binding efficiency and enzymatic activity.

Main Results:

• Several polyribonucleotide-binding proteins were isolated from blood plasma.
• Albumin and keratins (K1, K2e) were found to bind polypurine tracts.
• In vitro glycated albumin exhibited increased binding affinity for poly(A) and poly(G) compared to unmodified albumin.
• A 28 kDa polypyrimidine-binding protein demonstrated catalytic activity in hydrolyzing poly(U).

Conclusions:

• Blood plasma harbors specific proteins capable of binding to various RNA structures.
• Albumin's interaction with RNA is modulated by glycation.
• The identified 28 kDa protein possesses RNA-hydrolyzing enzymatic activity, suggesting a potential role in RNA metabolism.