1tf4
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| , resolution 1.9Å | |||||||
|---|---|---|---|---|---|---|---|
| Sites: | , , , , and | ||||||
| Ligands: | |||||||
| Gene: | BAMH1-PST1 FRAGMENT OF T. FUSC (Thermobifida fusca) | ||||||
| Activity: | Cellulase, with EC number 3.2.1.4 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
ENDO/EXOCELLULASE FROM THERMOMONOSPORA
OverviewOverview
Cellulase E4 from Thermomonospora fusca is unusual in that it has characteristics of both exo- and endo-cellulases. Here we report the crystal structure of a 68K M(r) fragment of E4 (E4-68) at 1.9 A resolution. E4-68 contains both a family 9 catalytic domain, exhibiting an (alpha/alpha)6 barrel fold, and a family III cellulose binding domain, having an antiparallel beta-sandwich fold. While neither of these folds is novel, E4-68 provides the first cellulase structure having interacting catalytic and cellulose binding domains. The complexes of E4-68 with cellopentaose, cellotriose and cellobiose reveal conformational changes associated with ligand binding and allow us to propose a catalytic mechanism for family 9 enzymes. We also provide evidence that E4 has two novel characteristics: first it combines exo- and endo-activities and second, when it functions as an exo-cellulase, it cleaves off cellotetraose units.
About this StructureAbout this Structure
1TF4 is a Single protein structure of sequence from Thermobifida fusca. Full crystallographic information is available from OCA.
ReferenceReference
Structure and mechanism of endo/exocellulase E4 from Thermomonospora fusca., Sakon J, Irwin D, Wilson DB, Karplus PA, Nat Struct Biol. 1997 Oct;4(10):810-8. PMID:9334746
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