Structural studies of the glycopeptides of B-chain of cinnamomin--a type II ribosome-inactivating protein by nuclear magnetic resonance.
Cinnamomin is a plant type II ribosome-inactivating protein (RIP) isolated from the seeds of Cinnamomum camphora. It consists of two nonidentical polypeptide chains (A- and B-chain) held together through one disulfide linkage. Its A- and B-chain contain 0.3% and 3.9% sugars respectively. The B-chain of cinnamomin was digested by pronase E and then the liberated glycopeptides were separated from non-glycopeptides by gel filtration chromatography on a Bio-Gel P-4 column. Three crude glycopeptides were obtained by continuing chromatography over anion-exchange resin (AG1-X2) in the buffer of 2% pyridine-acetic acid (pH 8.3) with a polygradient elution system. Through further purification by the gel filtration chromatography and HPLC, three major glycopeptides, GP1, GP2 and GP3 were obtained. Mainly by two-dimensional Nuclear Magnetic Resonance (NMR) including TOCSY, DQF-COSY, NOESY, HMQC and HMBC, their primary structures were analyzed as: Man\balpha1,3Man\balpha1,6(Man\balpha1,3)(Xyl\bbeta1,2)Man\bbeta1,4GlcNAc\bbeta1,4GlcNAc\bbeta1-(Gly-)Asn-Asn-Thr(GP1), Man\balpha1,6(Man\balpha1,3)(Xyl\bbeta1,2)Man\bbeta1,4GlcNAc\bbeta1,4(Fuc\balpha1,3)GlcNAc\bbeta1-Asn-Ala-Thr(GP2),Man\balpha1,6(Man\balpha1,3)Man\balpha1,6(Man\balpha 1,2 Man\balpha1,3)Man\bbeta1,4GlcNAc\bbeta1,4GlcNAc\bbeta1-(Ala-)Asn-Gly-Thr(GP3).
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Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China.
Li
Y
Y
Hou
F J
FJ
He
F
F
Zhang
N
N
Wu
H
H
Liu
W Y
WY
D020418:Algal Proteins; D002240:Carbohydrate Sequence; D006020:Glycopeptides / Q000737:chemistry*; D019770:Lauraceae / Q000737:chemistry*; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010940:Plant Proteins / Q000737:chemistry; D011506:Proteins / Q000737:chemistry*; D054790:Ribosome Inactivating Proteins, Type 2
D020418:Algal Proteins; D006020:Glycopeptides; D010940:Plant Proteins; D011506:Proteins; D054790:Ribosome Inactivating Proteins, Type 2; C061930:cinnamomin, Phytophthora cinnamomi