5U22 image
Entry Detail
PDB ID:
5U22
Keywords:
Title:
Structure of N2152 from Neocallimastix frontalis
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
2016-11-29
Release Date:
2017-06-14
Method Details:
Experimental Method:
Resolution:
1.75 Å
R-Value Free:
0.19
R-Value Work:
0.15
R-Value Observed:
0.15
Space Group:
P 1 21 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:N2152
Chain IDs:A
Chain Length:423
Number of Molecules:1
Biological Source:Neocallimastix frontalis
Primary Citation
Discovery and characterization of family 39 glycoside hydrolases from rumen anaerobic fungi with polyspecific activity on rare arabinosyl substrates.
J. Biol. Chem. 292 12606 12620 (2017)
PMID: 28588026 DOI: 10.1074/jbc.M117.789008

Abstact

Enzyme activities that improve digestion of recalcitrant plant cell wall polysaccharides may offer solutions for sustainable industries. To this end, anaerobic fungi in the rumen have been identified as a promising source of novel carbohydrate active enzymes (CAZymes) that modify plant cell wall polysaccharides and other complex glycans. Many CAZymes share insufficient sequence identity to characterized proteins from other microbial ecosystems to infer their function; thus presenting challenges to their identification. In this study, four rumen fungal genes (nf2152, nf2215, nf2523, and pr2455) were identified that encode family 39 glycoside hydrolases (GH39s), and have conserved structural features with GH51s. Two recombinant proteins, NF2152 and NF2523, were characterized using a variety of biochemical and structural techniques, and were determined to have distinct catalytic activities. NF2152 releases a single product, β1,2-arabinobiose (Ara2) from sugar beet arabinan (SBA), and β1,2-Ara2 and α-1,2-galactoarabinose (Gal-Ara) from rye arabinoxylan (RAX). NF2523 exclusively releases α-1,2-Gal-Ara from RAX, which represents the first description of a galacto-(α-1,2)-arabinosidase. Both β-1,2-Ara2 and α-1,2-Gal-Ara are disaccharides not previously described within SBA and RAX. In this regard, the enzymes studied here may represent valuable new biocatalytic tools for investigating the structures of rare arabinosyl-containing glycans, and potentially for facilitating their modification in industrial applications.

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