Characterization of Intrinsically Disordered Prostate Associated Gene (PAGE5) at Single Residue Resolution by NMR Spectroscopy

BACKGROUND: The Cancer-Testis antigens (CTA) are proteins expressed in human germ line and certain cancer cells. CTAs form a large gene family, representing 10% of X-chromosomal genes. They have high potential for cancer-specific immunotherapy. However, their biological functions are currently unknown. Prostate associated genes (PAGE) are characterized as CTAs. PAGE5 is one of six proteins belonging to this protein family, also called CT16. METHODOLOGY/PRINCIPAL FINDINGS: In this study we show, using bioinformatics, chromatographic and solution state NMR spectroscopic methods, that PAGE5 is an intrinsically disordered protein (IDP). CONCLUSION/SIGNIFICANCE: The study stands out as the first time structural characterization of the PAGE family protein and introduces how solution state NMR spectroscopy can be effectively utilized for identification of molecular recognition regions (MoRF) in IDPs, known often as transiently populated secondary structures.