Structural Basis for the Specificity of the Reducing End Xylose-releasing Exo-oligoxylanase from Bacillus halodurans C-125Fushinobu, S., Hidaka, M., Honda, Y., Wakagi, T., Shoun, H., Kitaoka, M.
(2005) J Biol Chem 280: 17180-17186
- PubMed: 15718242
- DOI: 10.1074/jbc.M413693200
- Primary Citation of Related Structures:
1WU6, 1WU5, 1WU4
- PubMed Abstract:
- Crystallization and preliminary X-ray analysis of reducing-end-xylose releasing exo-oligoxylanase (Rex) form Bacillus halodurans C-125
Honda, Y., Fushinobu, S., Hidaka, M., Wakagi, T., Shoun, H., Kitaoka, M.
() To be published --: --
- A family 8 glycoside hydrolase from Bacillus halodurans C-125 (BH2105) is a reducing end xylose-releasing exo-oligoxylanase
Honda, Y., Kitaoka, M.
(2004) J Biol Chem 279: 55097
Reducing end xylose-releasing exo-oligoxylanase from Bacillus halodurans C-125 (Rex) hydrolyzes xylooligosaccharides whose degree of polymerization is greater than or equal to 3, releasing the xylose unit at the reducing end. It is a unique exo-type ...
Reducing end xylose-releasing exo-oligoxylanase from Bacillus halodurans C-125 (Rex) hydrolyzes xylooligosaccharides whose degree of polymerization is greater than or equal to 3, releasing the xylose unit at the reducing end. It is a unique exo-type glycoside hydrolase that recognizes the xylose unit at the reducing end in a very strict manner, even discriminating the beta-anomeric hydroxyl configuration from the alpha-anomer or 1-deoxyxylose. We have determined the crystal structures of Rex in unliganded and complex forms at 1.35-2.20-A resolution and revealed the structural aspects of its three subsites ranging from -2 to +1. The structure of Rex was compared with those of endo-type enzymes in glycoside hydrolase subfamily 8a (GH-8a). The catalytic machinery of Rex is basically conserved with other GH-8a enzymes. However, subsite +2 is blocked by a barrier formed by a kink in the loop before helix alpha10. His-319 in this loop forms a direct hydrogen bond with the beta-hydroxyl of xylose at subsite +1, contributing to the specific recognition of anomers at the reducing end.
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