Xanthan lyase

In enzymology, a xanthan lyase (EC number|4.2.2.12) is an enzyme that catalyzes the chemical reaction of cleaving the beta-D-mannosyl-beta-D-1,4-glucuronosyl bond on the polysaccharide xanthan. This enzyme belongs to the family of lyases, specifically those carbon-oxygen lyases acting on polysaccharides. Xanthan lyase was first identified and partially-purified in 1987. [cite journal |author=Sutherland IW |title=Xanthan lyases--novel enzymes found in various bacterial species |journal=J. Gen. Microbiol. |volume=133 |issue=11 |pages=3129–34 |year=1987 |pmid=3446747]

Xanthan is a polysaccharide secreted by several bacteria, such as the plant pathogen "Xanthomonas campestris", and it consists of a main linear chain based on cellulose with side chains attached to alternate glucosyl (glucose) residues.cite journal |author=Hashimoto W, Miki H, Tsuchiya N, Nankai H, Murata K |title=Xanthan lyase of Bacillus sp. strain GL1 liberates pyruvylated mannose from xanthan side chains |journal=Appl. Environ. Microbiol. |volume=64 |issue=10 |pages=3765–8 |year=1998 |pmid=9758797 |url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=9758797] These side chains contain three monosaccharide residues. Xanthan lyase is produced by bacteria that degrade this polysaccharide, such as "Bacillus", "Corynebacterium" and "Paenibacillus" species.cite journal |author=Ruijssenaars HJ, de Bont JA, Hartmans S |title=A pyruvated mannose-specific xanthan lyase involved in xanthan degradation by Paenibacillus alginolyticus XL-1 |journal=Appl. Environ. Microbiol. |volume=65 |issue=6 |pages=2446–52 |year=1999 |pmid=10347025 |url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=10347025]

Industrial applications

Xanthan is used in industry as a thickening agent in foods and drinks, as a stabilizing agent for foams, as a means of enhancing oil recovery and in the manufacture of good such as paints, cosmetics and explosives. The use of xanthan lyase as a means of altering the physical properties of xanthans is an area of current research in biotechnology.

tructural studies

As of late 2007, 7 structures have been solved for this class of enzymes, with PDB accession codes PDB link|1J0M, PDB link|1J0N, PDB link|1X1H, PDB link|1X1I, PDB link|1X1J, PDB link|2E22, and PDB link|2E24. The enzyme from "Bacillus" is a monomer consisting of two domains: an alpha helical N-terminal domain, and a C-terminal domain composed of beta sheets. [cite journal |author=Hashimoto W, Nankai H, Mikami B, Murata K |title=Crystal structure of Bacillus sp. GL1 xanthan lyase, which acts on the side chains of xanthan |journal=J. Biol. Chem. |volume=278 |issue=9 |pages=7663–73 |year=2003 |pmid=12475987 |url=http://www.jbc.org/cgi/content/full/278/9/7663 |doi=10.1074/jbc.M208100200] The active site is a deep cleft located between these two domains.

References

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External links

::"The CAS registry number for this enzyme class is CAS registry|113573-69-6."

Gene Ontology (GO) codes