Functional analysis of a group A streptococcal glycoside hydrolase Spy1600 from family 84 reveals it is a β-N-acetylglucosaminidase and not a hyaluronidase

Sheldon, William L., Macauley, Matthew S., Taylor, Edward J., Robinson, Charlotte E., Charnock, Simon J., Davies, Gideon J., Vocadlo, David J. and Black, Gary W. (2006) Functional analysis of a group A streptococcal glycoside hydrolase Spy1600 from family 84 reveals it is a β-N-acetylglucosaminidase and not a hyaluronidase. Biochemical Journal, 399 . pp. 241-247. ISSN 0264-6021

Full content URL: http://dx.doi.org/10.1042/BJ20060307

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Abstract

Group A streptococcus (Streptococcus pyogenes) is the causative agent of severe invasive infections such as necrotizing fasciitis (the so-called 'flesh eating disease') and toxic-shock syndrome. Spy1600, a glycoside hydrolase from family 84 of the large superfamily of glycoside hydrolases, has been proposed to be a virulence factor. In the present study we show that Spy1600 has no activity toward galactosaminides or hyaluronan, but does remove beta-O-linked N-acetylglucosamine from mammalian glycoproteins--an observation consistent with the inclusion of eukaryotic O-glycoprotein 2-acetamido-2-deoxy-beta-D-glucopyranosidases within glycoside hydrolase family 84. Proton NMR studies, structure-reactivity studies for a series of fluorinated analogues and analysis of 1,2-dideoxy-2'-methyl-alpha-D-glucopyranoso-[2,1-d]-Delta2'-thiazoline as a competitive inhibitor reveals that Spy1600 uses a double-displacement mechanism involving substrate-assisted catalysis. Family 84 glycoside hydrolases are therefore comprised of both prokaryotic and eukaryotic beta-N-acetylglucosaminidases using a conserved catalytic mechanism involving substrate-assisted catalysis. Since these enzymes do not have detectable hyaluronidase activity, many family 84 glycoside hydrolases are most likely incorrectly annotated as hyaluronidases.

Additional Information:Group A streptococcus (Streptococcus pyogenes) is the causative agent of severe invasive infections such as necrotizing fasciitis (the so-called 'flesh eating disease') and toxic-shock syndrome. Spy1600, a glycoside hydrolase from family 84 of the large superfamily of glycoside hydrolases, has been proposed to be a virulence factor. In the present study we show that Spy1600 has no activity toward galactosaminides or hyaluronan, but does remove beta-O-linked N-acetylglucosamine from mammalian glycoproteins--an observation consistent with the inclusion of eukaryotic O-glycoprotein 2-acetamido-2-deoxy-beta-D-glucopyranosidases within glycoside hydrolase family 84. Proton NMR studies, structure-reactivity studies for a series of fluorinated analogues and analysis of 1,2-dideoxy-2'-methyl-alpha-D-glucopyranoso-[2,1-d]-Delta2'-thiazoline as a competitive inhibitor reveals that Spy1600 uses a double-displacement mechanism involving substrate-assisted catalysis. Family 84 glycoside hydrolases are therefore comprised of both prokaryotic and eukaryotic beta-N-acetylglucosaminidases using a conserved catalytic mechanism involving substrate-assisted catalysis. Since these enzymes do not have detectable hyaluronidase activity, many family 84 glycoside hydrolases are most likely incorrectly annotated as hyaluronidases.
Keywords:β-N-acetylglucosaminidase, mammalian glycoproteins, Spyl600, substrate-assisted catalysis
Subjects:C Biological Sciences > C700 Molecular Biology, Biophysics and Biochemistry
Divisions:College of Science > School of Life Sciences
ID Code:6165
Deposited On:18 Sep 2012 11:23

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