4PEU

Structure of the polysaccharide lyase-like protein Cthe_2159 from C. thermocellum, native form with Calcium bound

Summary for 4PEU

• Entry DOI: 10.2210/pdb4peu/pdb
• Descriptor: Uncharacterized protein, CALCIUM ION (3 entities in total)
• Functional Keywords: beta-helix, polysaccharide lyase, carbohydrate-binding, calcium-binding, unknown function
• Biological source: Clostridium thermocellum
• Cellular location: Cell membrane ; Lipid-anchor : A3DHD2
• Total number of polymer chains: 1
• Total formula weight: 32980.00

Authors

Close, D.W.,D'Angelo, S.,Bradbury, A.R.M. (deposition date: 2014-04-24, release date: 2014-10-01, Last modification date: 2023-12-27)

Primary citation

Close, D.W.,D'Angelo, S.,Bradbury, A.R.
A new family of beta-helix proteins with similarities to the polysaccharide lyases.
Acta Crystallogr.,Sect.D, 70:2583-2592, 2014

PubMed Abstract: Microorganisms that degrade biomass produce diverse assortments of carbohydrate-active enzymes and binding modules. Despite tremendous advances in the genomic sequencing of these organisms, many genes do not have an ascribed function owing to low sequence identity to genes that have been annotated. Consequently, biochemical and structural characterization of genes with unknown function is required to complement the rapidly growing pool of genomic sequencing data. A protein with previously unknown function (Cthe_2159) was recently isolated in a genome-wide screen using phage display to identify cellulose-binding protein domains from the biomass-degrading bacterium Clostridium thermocellum. Here, the crystal structure of Cthe_2159 is presented and it is shown that it is a unique right-handed parallel β-helix protein. Despite very low sequence identity to known β-helix or carbohydrate-active proteins, Cthe_2159 displays structural features that are very similar to those of polysaccharide lyase (PL) families 1, 3, 6 and 9. Cthe_2159 is conserved across bacteria and some archaea and is a member of the domain of unknown function family DUF4353. This suggests that Cthe_2159 is the first representative of a previously unknown family of cellulose and/or acid-sugar binding β-helix proteins that share structural similarities with PLs. Importantly, these results demonstrate how functional annotation by biochemical and structural analysis remains a critical tool in the characterization of new gene products.

PubMed: 25286843
DOI: 10.1107/S1399004714015934

Experimental method

X-RAY DIFFRACTION (1.8001 Å)