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The abp gene in Geobacillus stearothermophilus T‐6 encodes a GH27 β‐ l ‐arabinopyranosidase
Author(s) -
Salama Rachel,
Alalouf Onit,
Tabachnikov Orly,
Zolotnitsky Gennady,
Shoham Gil,
Shoham Yuval
Publication year - 2012
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2012.05.062
Subject(s) - geobacillus stearothermophilus , chemistry , residue (chemistry) , arabinogalactan , glycoside hydrolase , stereochemistry , enzyme , biochemistry , polysaccharide , thermophile
In this study we demonstrate that the abp gene in Geobacillus stearothermophilus T‐6 encodes a family 27 glycoside hydrolase β‐ l ‐arabinopyranosidase. The catalytic constants towards the chromogenic substrate pNP‐β‐ l ‐arabinopyranoside were 0.8 ± 0.1 mM, 6.6 ± 0.3 s −1 , and 8.2 ± 0.3 s −1 mM −1 for K m , k cat and k cat /K m , respectively. 13 C NMR spectroscopy unequivocally showed that Abp is capable of removing β‐ l ‐arabinopyranose residues from the natural arabino‐polysaccharide, larch arabinogalactan. Most family 27 enzymes are active on galactose and contain a conserved Asp residue, whereas in Abp this residue is Ile67, which shifts the specificity of the enzyme towards arabinopyranoside.