TY - JOUR
T1 - The ß-1,4-endogalactanase A gene from Aspergillus niger is specifically induced on arabinose and galacturonic acid and plays an important role in the degradation of pectic hairy regions
AU - de Vries, R.P.
AU - Parenicova, L.
AU - Hinz, S.W.A.
AU - Kester, H.C.M.
AU - Beldman, G.
AU - Benen, J.A.E.
AU - Visser, J.
PY - 2002
Y1 - 2002
N2 - The Aspergillus nigerß-1,4-endogalactanase encoding gene (galA) was cloned and characterized. The expression of galA in A. niger was only detected in the presence of sugar beet pectin, d-galacturonic acid and l-arabinose, suggesting that galA is coregulated with both the pectinolytic genes as well as the arabinanolytic genes. The corresponding enzyme, endogalactanase A (GALA), contains both active site residues identified previously for the Pseudomonas fluorescensß-1,4-endogalactanase.
The galA gene was overexpressed to facilitate purification of GALA. The enzyme has a molecular mass of 48.5 kDa and a pH optimum between 4 and 4.5. Incubations of arabinogalactans of potato, onion and soy with GALA resulted initially in the release of d-galactotriose and d-galactotetraose, whereas prolonged incubation resulted in d-galactose and d-galactobiose, predominantly. MALDI-TOF analysis revealed the release of l-arabinose substituted d-galacto-oligosaccharides from soy arabinogalactan. This is the first report of the ability of a ß-1,4-endogalactanase to release substituted d-galacto-oligosaccharides. GALA was not active towards d-galacto-oligosaccharides that were substituted with d-glucose at the reducing end.
AB - The Aspergillus nigerß-1,4-endogalactanase encoding gene (galA) was cloned and characterized. The expression of galA in A. niger was only detected in the presence of sugar beet pectin, d-galacturonic acid and l-arabinose, suggesting that galA is coregulated with both the pectinolytic genes as well as the arabinanolytic genes. The corresponding enzyme, endogalactanase A (GALA), contains both active site residues identified previously for the Pseudomonas fluorescensß-1,4-endogalactanase.
The galA gene was overexpressed to facilitate purification of GALA. The enzyme has a molecular mass of 48.5 kDa and a pH optimum between 4 and 4.5. Incubations of arabinogalactans of potato, onion and soy with GALA resulted initially in the release of d-galactotriose and d-galactotetraose, whereas prolonged incubation resulted in d-galactose and d-galactobiose, predominantly. MALDI-TOF analysis revealed the release of l-arabinose substituted d-galacto-oligosaccharides from soy arabinogalactan. This is the first report of the ability of a ß-1,4-endogalactanase to release substituted d-galacto-oligosaccharides. GALA was not active towards d-galacto-oligosaccharides that were substituted with d-glucose at the reducing end.
KW - subtilis var amylosacchariticus
KW - cell wall polysaccharides
KW - bacillus-subtilis
KW - hemicellulolytic enzymes
KW - purification
KW - expression
KW - sequence
KW - galactanases
KW - aculeatus
KW - endo-1,4-beta-d-galactanase
U2 - 10.1046/j.1432-1033.2002.03199.x
DO - 10.1046/j.1432-1033.2002.03199.x
M3 - Article
SN - 0014-2956
VL - 269
SP - 4985
EP - 4993
JO - European Journal of Biochemistry
JF - European Journal of Biochemistry
IS - 20
ER -