Structural Characterization and Interaction with RCA120 of a Highly Sulfated Keratan Sulfate from Blue Shark (Prionace glauca) Cartilage.

Jing Zhao,Guangli Yu,Qinying Li,Robert Linhardt,Fuming Zhang,Guoyun Li,Xindi Shan,Chao Cai,Xiaoliang Zhao

doi:10.3390/md16040128

Abstract

As an important glycosaminoglycan, keratan sulfate (KS) mainly exists in corneal and cartilage, possessing various biological activities. In this study, we purified KS from blue shark (Prionace glauca) cartilage and prepared KS oligosaccharides (KSO) through keratanase II-catalyzed hydrolysis. The structures of KS and KSO were characterized using multi-dimensional nuclear magnetic resonance (NMR) spectra and liquid chromatography-mass spectrometry (LC-MS). Shark cartilage KS was highly sulfated and modified with ~2.69% N-acetylneuraminic acid (NeuAc) through α(2,3)-linked to galactose. Additionally, KS exhibited binding affinity to Ricinus communis agglutinin I (RCA120) in a concentration-dependent manner, a highly toxic lectin from beans of the castor plant. Furthermore, KSO from dp2 to dp8 bound to RCA120 in the increasing trend while the binding affinity of dp8 was superior to polysaccharide. These results define novel structural features for KS from Prionace glauca cartilage and demonstrate the potential application on ricin-antidote exploitation.

Highlights

IntroductionGlycosaminoglycans (GAGs) are anionic, linear polysaccharides consisting of repeating disaccharide units of hexuronic acid (D-glucuronic acid, GlcA, and/or its C5-epimer L-iduronic acid, IdoA) or hexose (D-galactose) and hexosamine (D-glucosamine, GlcN, or D-galactosamine, GalN)
A series of KS oligosaccharides (KSO) were obtained by keratan sulfate (KS) digestion with keratanase II
The structure of KS and KSO were confirmed by multi-dimensional nuclear magnetic resonance (NMR) spectra and HILIC-FTMS

Summary

Introduction

Glycosaminoglycans (GAGs) are anionic, linear polysaccharides consisting of repeating disaccharide units of hexuronic acid (D-glucuronic acid, GlcA, and/or its C5-epimer L-iduronic acid, IdoA) or hexose (D-galactose) and hexosamine (D-glucosamine, GlcN, or D-galactosamine, GalN). KS is the only type of GAGs without uronic acid, and mainly composed of alternating repeating disaccharide unit of β (1,3)-linked galactose (Gal) and β (1,4)-linked N-acetylglucosamine (GlcNAc) with sulfation occurring at the C6 of both saccharide units [3,4,5]. The degree of sulfation of KS varies in different tissues, such as cornea [6], cartilage [7], and brain [8].

Methods

Results

Conclusion