title: Unusual microbial xylanases from insect guts.
abstract: Recombinant DNA technologies enable the direct isolation and expression of novel genes from biotopes containing complex consortia of uncultured microorganisms. In this study, genomic libraries were constructed from microbial DNA isolated from insect intestinal tracts from the orders Isoptera (termites) and Lepidoptera (moths). Using a targeted functional assay, these environmental DNA libraries were screened for genes that encode proteins with xylanase activity. Several novel xylanase enzymes with unusual primary sequences and novel domains of unknown function were discovered. Phylogenetic analysis demonstrated remarkable distance between the sequences of these enzymes and other known xylanases. Biochemical analysis confirmed that these enzymes are true xylanases, which catalyze the hydrolysis of a variety of substituted beta-1,4-linked xylose oligomeric and polymeric substrates and produce unique hydrolysis products. From detailed polyacrylamide carbohydrate electrophoresis analysis of substrate cleavage patterns, the xylan polymer binding sites of these enzymes are proposed.
authors.affiliation: Diversa Corporation, San Diego, CA 92121, USA.
authors.forename: YaLi
authors.initials: Y
authors.lastname: Brennan
authors.forename: Walter N
authors.initials: WN
authors.lastname: Callen
authors.forename: Leif
authors.initials: L
authors.lastname: Christoffersen
authors.forename: Paul
authors.initials: P
authors.lastname: Dupree
authors.forename: Florence
authors.initials: F
authors.lastname: Goubet
authors.forename: Shaun
authors.initials: S
authors.lastname: Healey
authors.forename: Myrian
authors.initials: M
authors.lastname: Hernández
authors.forename: Martin
authors.initials: M
authors.lastname: Keller
authors.forename: Ke
authors.initials: K
authors.lastname: Li
authors.forename: Nisha
authors.initials: N
authors.lastname: Palackal
authors.forename: Ana
authors.initials: A
authors.lastname: Sittenfeld
authors.forename: Giselle
authors.initials: G
authors.lastname: Tamayo
authors.forename: Steve
authors.initials: S
authors.lastname: Wells
authors.forename: Geoffrey P
authors.initials: GP
authors.lastname: Hazlewood
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Mathur
authors.forename: Jay M
authors.initials: JM
authors.lastname: Short
authors.forename: Dan E
authors.initials: DE
authors.lastname: Robertson
authors.forename: Brian A
authors.initials: BA
authors.lastname: Steer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001419:Bacteria / Q000201:enzymology* / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis / Q000302:isolation & purification; D004271:DNA, Fungal / Q000032:analysis / Q000302:isolation & purification; D004064:Digestive System / Q000382:microbiology*; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D005658:Fungi / Q000201:enzymology* / Q000235:genetics; D015723:Gene Library; D020049:Isoptera / Q000382:microbiology*; D008969:Molecular Sequence Data; D009036:Moths / Q000382:microbiology*; D010802:Phylogeny; D016415:Sequence Alignment
chemical_list: D004269:DNA, Bacterial; D004271:DNA, Fungal; D043364:Endo-1,4-beta Xylanases