Structural Analysis of Bikunin Glycosaminoglycan

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• 作者：Lianli Chi ; Jeremy J. Wolff ; Tatiana N. Laremore ; Odile F. Restaino ; Jin Xie ; Chiara Schiraldi ; Toshihiko Toida ; I. Jonathan Amster ; Robert J. Linhardt
• 刊名：Journal of the American Chemical Society
• 出版年：2008
• 出版时间：February 27, 2008
• 年：2008
• 卷：130
• 期：8
• 页码：2617 - 2625
• 全文大小：286K
• 年卷期：v.130,no.8(February 27, 2008)
• ISSN：1520-5126

文摘

The structure of an intact glycosaminoglycan (GAG) chain of the bikunin proteoglycan (PG) wasanalyzed using a combined top-down and bottom-up sequencing strategy. PGs are proteins with one ormore linear, high-molecular weight, sulfated GAG polysaccharides O-linked to serine or threonine residues.GAGs are often responsible for the biological functions of PGs, and subtle variations in the GAG structurehave pronounced physiological effects. Bikunin is a serine protease inhibitor found in human amniotic fluid,plasma, and urine. Bikunin is posttranslationally modified with a chondroitin sulfate (CS) chain, O-linked toa serine residue of the core protein. Recent studies have shown that the CS chain of bikunin plays animportant role in the physiological and pathological functions of this PG. While no PG or GAG has yetbeen sequenced, bikunin, the least complex PG, offers a compelling target. Electrospray ionization Fouriertransform-ion cyclotron resonance mass spectrometry (ESI FTICR-MS) permitted the identification of severalmajor components in the GAG mixture having molecular masses in a range of 5505-7102 Da. This is thefirst report of a mass spectrum of an intact GAG component of a PG. FTICR-MS analysis of a size-uniformfraction of bikunin GAG mixture obtained by preparative polyacrylamide gel electrophoresis, allowed thedetermination of chain length and number of sulfo groups in the intact GAGs.