4EKJ

Crystal structure of a monomeric beta-xylosidase from Caulobacter crescentus CB15

Summary for 4EKJ

• Entry DOI: 10.2210/pdb4ekj/pdb
• Descriptor: Beta-xylosidase, SULFATE ION (3 entities in total)
• Functional Keywords: tim-barrel fold, hemicellulase, hydrolase
• Biological source: Caulobacter vibrioides
• Total number of polymer chains: 1
• Total formula weight: 56785.89

Authors

Santos, C.R.,Polo, C.C.,Correa, J.M.,Simao, R.C.G.,Seixas, F.A.V.,Murakami, M.T. (deposition date: 2012-04-09, release date: 2012-09-26, Last modification date: 2023-09-13)

Primary citation

Santos, C.R.,Polo, C.C.,Correa, J.M.,Simao, R.C.,Seixas, F.A.,Murakami, M.T.
The accessory domain changes the accessibility and molecular topography of the catalytic interface in monomeric GH39 beta-xylosidases.
Acta Crystallogr.,Sect.D, 68:1339-1345, 2012

PubMed Abstract: β-Xylosidases (EC 3.2.1.37) are among the principal glycosyl hydrolases involved in the breakdown of hemicelluloses, catalyzing the reduction of xylooligosaccharides to free xylose. All GH39 β-xylosidases structurally characterized to date display a modular multi-domain organization that assembles a tetrameric quaternary structure. In this work, the crystal structure and the SAXS molecular envelope of a new GH39 β-xylosidase from Caulobacter crescentus (CcXynB2) have been determined. Interestingly, CcXynB2 is a monomer in solution and comparative structural analyses suggest that the shortened C-terminus prevents the formation of a stable tetramer. Moreover, CcXynB2 has a longer loop from the auxiliary domain (the long α-helix-containing loop) which makes a number of polar and hydrophobic contacts with the parental (α/β)(8)-barrel domain, modifying the accessibility and the molecular topography of the catalytic interface. These interactions also maintain the accessory domain tightly linked to the catalytic core, which may be important for enzyme function and stability.

PubMed: 22993088
DOI: 10.1107/S0907444912028491

Experimental method

X-RAY DIFFRACTION (2.5 Å)