Unusual role of the 2-OH group of oligosaccharide substrates in the mechanism of Bacillus 1,3-1,4-β-glucanase

Antoni Planas, Juan Nieto, Mireia Abel, Antoni Segade

Producción científica: Artículo en revista indizadaArtículorevisión exhaustiva

2 Citas (Scopus)

Resumen

In the mechanism of retaining β-glycosidases, the 2-hydroxyl group of the substrate in the monosaccharyl unit involved in catalysis (subsite - 1) is believed to play an important role through hydrogen bonding interactions with protein residues that are optimized at the transition state. Commonly, removal of the 2-OH group of the substrate results in a 10-12 kcal.mol-1 transition state destabilization. However, this effect seems not to be general as reported here for Bacillus 1,3-1,4-β-glucanase, a family 16 retaining endo-glycosidase. A p-nitrophenyl 2-deoxy tetrasaccharide substrate was synthesized to probe the involvement of the 2-OH group in catalysis. Comparative kinetics with wild-type and subsite +1 mutants show that the 2-deoxy analog is a better substrate than the corresponding 2-hydroxy substrate. It is tentatively proposed that the 2-deoxy analog adopts a different conformation upon binding that compensates for the lack of the 2-OH substituent.

Idioma originalInglés
Páginas (desde-hasta)223-231
Número de páginas9
PublicaciónBiocatalysis and Biotransformation
Volumen21
N.º4-5
DOI
EstadoPublicada - ago 2003
Evento5th Carbohydrate Bioengineering Meeting - GRONINGEN, Países Bajos
Duración: 6 abr 20039 abr 2003

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