tailieunhanh - Báo cáo khoa học: Structural basis for substrate recognition by Erwinia chrysanthemi GH30 glucuronoxylanase

Xylanase A from the phytopathogenic bacteriumErwinia chrysanthemiis classified as a glycoside hydrolase family 30 enzyme (previously in family 5) and is specialized for degradation of glucuronoxylan. The recombinant enzyme was crystallized with the aldotetraouronic acidb-D-xylopyranosyl-(1fi4)-[4-O-methyl-a-D-glucuronosyl-(1 fi2)]-b-D-xylopyranosyl-(1 fi4)-D-xylose as a ligand. | 1FEBS Journal Structural basis for substrate recognition by Erwinia chrysanthemi GH30 glucuronoxylanase 1ra -i v i 2i i i3t- Iirr3 i- -i2 Lubica Urbániková Maria Vrsanska Kristian B. R. M0rkeberg Krogh Tine Hoff and Peter Biely 1 Institute of Molecular Biology Slovak Academy of Sciences Bratislava Slovakia 2 Institute of Chemistry Center of Glycomics Slovak Academy of Sciences Bratislava Slovakia 3 Novozymes A S Bagsvaerd Denmark Keywords crystal structure with ligand Erwinia chrysanthemi GH30 glucuronoxylan-specific xylanase substrate recognition Correspondence P. Biely Institute of Chemistry Center of Glycomics Slovak Academy of Sciences Dubravska cesta 9 SK-845 38 Bratislava Slovakia Fax 421 2 5941 0222 Tel 421 2 5941 0275 E-mail chempbsa@ Received 17 December 2010 revised 10 April 2011 accepted 13 April 2011 doi Xylanase A from the phytopathogenic bacterium Erwinia chrysanthemi is classified as a glycoside hydrolase family 30 enzyme previously in family 5 and is specialized for degradation of glucuronoxylan. The recombinant enzyme was crystallized with the aldotetraouronic acid b-D-xylopyranosyl- 1 fi 4 - 4-O-methyl-a-D-glucuronosyl- 1 fi 2 -b-D-xylopyranosyl- 1 fi 4 -D-xylose as a ligand. The crystal structure of the enzyme-ligand complex was solved at A resolution. The ligand xylotriose moiety occupies subsites -1 -2 and -3 whereas the methyl glucuronic acid residue attached to the middle xylopyranosyl residue of xylotriose is bound to the enzyme through hydrogen bonds to five amino acids and by the ionic interaction of the methyl glucuronic acid carboxylate with the positively charged guan-idinium group of Arg293. The interaction of the enzyme with the methyl glucuronic acid residue appears to be indispensable for proper distortion of the xylan chain and its effective hydrolysis. Such a distortion does not occur with linear b-1 4-xylooligosaccharides which are hydrolyzed by the enzyme at a negligible .

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