The abp gene in Geobacillus stearothermophilus T-6 encodes a GH27 β-L-arabinopyranosidase.
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.
Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Rachel
R
Salama
Onit
O
Alalouf
Orly
O
Tabachnikov
Gennady
G
Zolotnitsky
Gil
G
Shoham
Yuval
Y
Shoham
D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D005685:Galactans / Q000737:chemistry; D001411:Geobacillus stearothermophilus / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000235:genetics; D006027:Glycosides / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007532:Isoleucine / Q000737:chemistry; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008957:Models, Genetic; D008969:Molecular Sequence Data; D005810:Multigene Family; D011134:Polysaccharides / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D013696:Temperature; D013997:Time Factors
D005685:Galactans; D006027:Glycosides; D011134:Polysaccharides; D007532:Isoleucine; C030080:araban; D006026:Glycoside Hydrolases