Related Experiment Videos
A novel family 8 xylanase, functional and physicochemical characterization
Tony Collins1, Marie-Alice Meuwis, Ingeborg Stals
1Laboratory of Biochemistry, Institute of Chemistry B6, University of Liège, B-4000 Liège, Belgium.
The Journal of Biological Chemistry
|June 29, 2002
Summary
Researchers discovered a novel psychrophilic xylanase from Antarctic bacteria. This unique enzyme, belonging to glycosyl hydrolase family 8, exhibits distinct properties and catalytic mechanisms compared to other known xylanases.
Area of Science:
- Enzymology
- Microbiology
- Biochemistry
Background:
- Xylanases are typically classified into glycosyl hydrolase families 10 and 11.
- These enzymes often show an inverse relationship between their isoelectric point (pI) and molecular mass.
- Known xylanases predominantly operate via retention of anomeric configuration during hydrolysis.
Purpose of the Study:
- To characterize a novel psychrophilic xylanase from Pseudoalteromonas haloplanktis.
- To determine the classification, catalytic mechanism, and substrate specificity of this unique enzyme.
- To investigate the evolutionary relationships within glycosyl hydrolase family 8.
Main Methods:
- Isolation and characterization of a psychrophilic xylanase from Antarctic bacterium Pseudoalteromonas haloplanktis.
- Nuclear Magnetic Resonance (NMR) analysis to elucidate the hydrolysis mechanism.
- Enzyme activity assays (xylanase, cellulase, chitosanase, lichenase) and kinetic studies.
- Phylogenetic analysis to construct an evolutionary tree of family 8 enzymes.
Main Results:
- A novel psychrophilic xylanase belonging to glycosyl hydrolase family 8 was isolated.
- This enzyme possesses a high pI and high molecular mass, deviating from typical family 10 and 11 xylanases.
- NMR analysis revealed hydrolysis with inversion of anomeric configuration, unlike the retaining mechanism of other xylanases.
- The enzyme exhibits high catalytic activity at low temperatures and low thermal stability, with a broad substrate-binding cleft.
- Phylogenetic analysis identified six distinct clusters within family 8, suggesting a unique (alpha/alpha)6 fold.
Conclusions:
- This study reports a novel family 8 xylanase with unique biochemical and catalytic properties.
- The enzyme's mechanism of action (inversion) and structural features (high pI, high molecular mass, broad cleft) distinguish it from other known xylanases.
- The findings expand the known diversity within glycosyl hydrolase family 8 and suggest distinct evolutionary pathways.