Laboratory of Organic Biochemistry

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Professor
Yasuhiro KAJIHARA
mail kajihara[a]chem.sci.osaka-u.ac.jp
Associate Professor
Masayuki izumi
mail mizumi[a]chem.sci.osaka-u.ac.jp
Assistant Professor
Ryo Okamoto
mail rokamoto[a]chem.sci.osaka-u.ac.jp
Fields

Life Science

Belong

Graduate School of Science

Location

Toyonaka

Research Theme

1) Chemical synthesis of oligosaccharides 2) Chemical synthesis of glycoproteins and glycopeptides 3) Elucidation of oligosaccharide functions 4) Elucidation of plant oligosaccharides

Chemical Synthesis of Glycoproteins

The oligosaccharides of protein have been thought to concern with protein conformation, dynamics, protein trafficking and glycoprotein lifetime in blood. We have examined synthesis of homogeneous glycoproteins having human complex type oligosaccharide in order to evaluate oligosaccharide functions. We have synthesized several small glycoproteins (amino acids 40-76 residues), erythropoietin analogue (amino acids 166 residues), and co-stimulate glycoprotein of T-cell (amino acids 120 residues). In order to synthesize these glycoproteins, the polypeptide sequence of target glycoprotein were divided into several segments and these were synthesized by solid phase peptide synthesis. After prepared both glycopeptide-thioester and peptide, these were coupled by repetitive Native Chemical Ligation (NCL). After construction of the glycosylated polypeptide chain, we examined folding experiments and evaluated effect of oligosaccharide during protein folding process. In addition, glycoproteins folded was analyzed its structure by NMR and CD spectra in order to evaluate conformational differences between glycosylated and nonglycosylated proteins. In our laboratory, we would like to elucidate oligosaccharide functions by use of such chemical approach.

0Glycoprotein synthesized by chemical methods

Bibliography

K. Hirano, D. Macmillan, K. Tezuka, T. Tsuji, Y. Kajihara Design and Synthesis of Homogeneous Erythropoietin Analogue with Two Human Complex-Type Sialyloligosaccharides: Combined Use of Chemical and Bacterial Protein Expression Methods Angew. Chem. Int. Ed 48 , 9557 - 9560 (2009)

M. Murakami, R. Okamoto, M. Izumi, Y. Kajihara Chemical Synthesis of an Erythropoietin Glycoform Containing a Complex-type Disialyloligosaccharide Angew. Chem. Int. Ed 51 , 3567 - 3572 (2012)

Contact

kajihara[a]chem.sci.osaka-u.ac.jp

http://www.chem.sci.osaka-u.ac.jp/lab/kajihara/en_index.html

http://www.chem.sci.osaka-u.ac.jp/lab/kajihara/en_index.html