4FMV

Crystal Structure Analysis of a GH30 Endoxylanase from Clostridium papyrosolvens C71

Summary for 4FMV

• Entry DOI: 10.2210/pdb4fmv/pdb
• Descriptor: Glucuronoarabinoxylan endo-1,4-beta-xylanase (2 entities in total)
• Functional Keywords: alpha beta barrel, (beta/alpha)8 barrel, hydrolase
• Biological source: Clostridium papyrosolvens
• Total number of polymer chains: 1
• Total formula weight: 43939.87

Authors

Bales, E.B.,Smith, J.K.,St John, F.J.,Hurlbert, J.C. (deposition date: 2012-06-18, release date: 2013-06-19, Last modification date: 2024-02-28)

Primary citation

St John, F.J.,Dietrich, D.,Crooks, C.,Pozharski, E.,Gonzalez, J.M.,Bales, E.,Smith, K.,Hurlbert, J.C.
A novel member of glycoside hydrolase family 30 subfamily 8 with altered substrate specificity.
Acta Crystallogr.,Sect.D, 70:2950-2958, 2014

PubMed Abstract: Endoxylanases classified into glycoside hydrolase family 30 subfamily 8 (GH30-8) are known to hydrolyze the hemicellulosic polysaccharide glucuronoxylan (GX) but not arabinoxylan or neutral xylooligosaccharides. This is owing to the specificity of these enzymes for the α-1,2-linked glucuronate (GA) appendage of GX. Limit hydrolysis of this substrate produces a series of aldouronates each containing a single GA substituted on the xylose penultimate to the reducing terminus. In this work, the structural and biochemical characterization of xylanase 30A from Clostridium papyrosolvens (CpXyn30A) is presented. This xylanase possesses a high degree of amino-acid identity to the canonical GH30-8 enzymes, but lacks the hallmark β8-α8 loop region which in part defines the function of this GH30 subfamily and its role in GA recognition. CpXyn30A is shown to have a similarly low activity on all xylan substrates, while hydrolysis of xylohexaose revealed a competing transglycosylation reaction. These findings are directly compared with the model GH30-8 enzyme from Bacillus subtilis, XynC. Despite its high sequence identity to the GH30-8 enzymes, CpXyn30A does not have any apparent specificity for the GA appendage. These findings confirm that the typically conserved β8-α8 loop region of these enzymes influences xylan substrate specificity but not necessarily β-1,4-xylanase function.

PubMed: 25372685
DOI: 10.1107/S1399004714019531

Experimental method

X-RAY DIFFRACTION (2.01 Å)