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Chikusa ku, Japan

Kato K.,Japan Institute for Molecular Science | Kato K.,Nagoya City University | Kato K.,Ochanomizu University | Kato K.,GLYENCE Co. | Kato K.,Japan Science and Technology Agency
Advances in Experimental Medicine and Biology | Year: 2012

Although many proteins in living systems are modified with carbohydrate chains, the current structural proteomics is mainly focused on naked proteins because heterogeneous and flexible properties of the sugar chains preclude traditional structural biology approaches. In view of the situation, we developed a systematic method for structural glycomics. The 3D HPLC mapping method has enabled glycosylation profiling at molecular, cellular and tissue levels and also provided a vast array of standard oligosaccharides as useful tools for comprehensive analyses of structures and functions of sugar chains. The use of 920-MHz ultra-high field NMR spectroscopy in conjunction with stable isotope labelling of glycans provided information on structures, dynamics and interactions of glycoconjugates at atomic resolution. This chapter outlines the structural glycomic approach and illustrates several examples of its applications to address the underlying mechanisms of (1) glycoform-dependent antibody effector functions promoted through the interaction between immunoglobulin G and Fcγ receptor and (2) interaction of amyloid β with clusters of the ganglioside GM1 as a crucial step in Alzheimer's disease. On the basis of our findings, the structural basis of these cell surface events is discussed. © 2012 Springer Science+Business Media, LLC. Source

Miyagawa S.,Osaka University | Maeda A.,Osaka University | Kawamura T.,Osaka University | Ueno T.,Osaka University | And 6 more authors.
Glycobiology | Year: 2014

After producing α1-3-galactosyltransferase knockout (GKO) pigs, most of the organs of these pigs showed less antigenicity to the human body. However, wild-type adult pig islets (API) that originally contained negligible levels of α-galactosidase now showed a clear antigenicity to human serum. In this study, N-glycans were isolated from both APIs and human islets. Their structures were then analyzed by a mapping technique based on their high-performance liquid chromatography elution positions and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometric data. Both preparations contained substantial amounts of high-mannose structures. The N-glycans from human islets were separated into 17 neutral, 8 mono-sialyl and 4 di-sialyl glycans, and the API glycans were comprised of 11 neutral, 8 mono-sialyl, 3 di-sialyl, 2 mono-sulfated, 3 mono-sialyl-mono-sulfated and 1 di-sulfated glycans. Among them, the API preparation contained one neutral, five mono-sialyl glycans and six sulfated glycans that were not detected in human islets. The structures of 9 of these 12 could be clearly determined. In addition, a study of the sulfate-depleted API suggests that sulfate residues could be antigenic to humans. The data herein will be helpful for future studies of the antigenicity associated with API. © The Author 2013. Source

Kato K.,Japan Institute for Molecular Science | Kato K.,Nagoya City University | Kato K.,Ochanomizu University | Kato K.,GLYENCE Co. | And 2 more authors.
Progress in Nuclear Magnetic Resonance Spectroscopy | Year: 2010

A paper published in Progress in Nuclear Magnetic Resonance Spectroscopy informs about stable-isotope-assisted NMR approaches to glycoproteins using immunoglobulin G (IgG) as a model system. The paper describes about the application of the stable-isotope-assisted NMR approach to structural analyses of glycoprotein glycans using IgG as a model system. IgG is described as a multi-domain glycoprotein with a molecular mass of 150 kDa, functioning as the major class of antibodies in the immune system. Three-dimensional structures have been determined by X-ray crystallographic analyses and are available for intact IgG molecules and for a proteolytic fragment Fc. Two methods are employed for stable-isotope-labeling of IgG-Fc glycans. These two methods include metabolic labeling through biosynthetic pathways of production vehicles and in vitro enzymatic attachment of isotopically labeled monosaccharide(s) onto the non-reducing end of the Fc glycans. Source

Kamiya Y.,Japan Institute for Molecular Science | Kamiya Y.,Nagoya City University | Satoh T.,Nagoya City University | Kato K.,Japan Institute for Molecular Science | And 3 more authors.
Biochimica et Biophysica Acta - General Subjects | Year: 2012

Background: N-linked oligosaccharides operate as tags for protein quality control, consigning glycoproteins to different fates, i.e. folding in the endoplasmic reticulum (ER), vesicular transport between the ER and the Golgi complex, and ER-associated degradation of glycoproteins, by interacting with a panel of intracellular lectins in the early secretory pathway. Scope of review: This review summarizes the current state of knowledge regarding the molecular and structural basis for glycoprotein-fate determination in cells that is achieved through the actions of the intracellular lectins and its partner proteins. Major conclusions: Cumulative frontal affinity chromatography (FAC) data demonstrated that the intracellular lectins exhibit distinct sugar-binding specificity profiles. The glycotopes recognized by these lectins as fate determinants are embedded in the triantennary structures of the high-mannose-type oligosaccharides and are exposed upon trimming of the outer glucose and mannose residues during the N-glycan processing pathway. Furthermore, recently emerged 3D structural data offer mechanistic insights into functional interplay between an intracellular lectin and its binding partner in the early secretory pathway. General significance: Structural biology approaches in conjunction with FAC methods provide atomic pictures of the mechanisms behind the glycoprotein-fate determination in cells. This article is a part of a Special issue entitled: Glycoproteomics. © 2011 Elsevier B.V. All rights reserved. Source

Mizushima T.,Nagoya City University | Yagi H.,Nagoya City University | Takemoto E.,Nagoya City University | Shibata-Koyama M.,Kyowa Hakko Kirin Co. | And 8 more authors.
Genes to Cells | Year: 2011

Removal of the fucose residue from the N-glycans of the Fc portion of immunoglobulin G (IgG) results in a dramatic enhancement of antibody-dependent cellular cytotoxicity (ADCC) through improved affinity for Fcγ receptor IIIa (FcγRIIIa). Here, we present the 2.2-Å structure of the complex formed between nonfucosylated IgG1-Fc and a soluble form of FcγRIIIa (sFcγRIIIa) with two N-glycosylation sites. The crystal structure shows that one of the two N-glycans of sFcγRIIIa mediates the interaction with nonfucosylated Fc, thereby stabilizing the complex. However, fucosylation of the Fc N-glycans inhibits this interaction, because of steric hindrance, and furthermore, negatively affects the dynamics of the receptor binding site. Our results offer a structural basis for improvement in ADCC of therapeutic antibodies by defucosylation. © 2011 The Authors. Journal compilation © 2011 by the Molecular Biology Society of Japan/Blackwell Publishing Ltd. Source

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