3VLA

Crystal structure of edgp

Summary for 3VLA

• Entry DOI: 10.2210/pdb3vla/pdb
• Related: 3VL8 3VL9 3VLB
• Descriptor: EDGP, 2-acetamido-2-deoxy-beta-D-glucopyranose (3 entities in total)
• Functional Keywords: extracellular, inhibitor, plant protein
• Biological source: Daucus carota (carrot)
• Total number of polymer chains: 1
• Total formula weight: 44528.02

Authors

Yoshizawa, T.,Shimizu, T.,Hirano, H.,Sato, M.,Hashimoto, H. (deposition date: 2011-11-30, release date: 2012-04-18, Last modification date: 2020-07-29)

Primary citation

Yoshizawa, T.,Shimizu, T.,Hirano, H.,Sato, M.,Hashimoto, H.
Structural basis for inhibition of xyloglucan-specific endo-beta-1,4-glucanase (XEG) by XEG-protein inhibitor
J.Biol.Chem., 287:18710-18716, 2012

PubMed Abstract: Microorganisms such as plant pathogens secrete glycoside hydrolases (GHs) to digest the polysaccharide chains of plant cell walls. The degradation of cell walls by these enzymes is a crucial step for nutrition and invasion. To protect the cell wall from these enzymes, plants secrete glycoside hydrolase inhibitor proteins (GHIPs). Xyloglucan-specific endo-β-1,4-glucanase (XEG), a member of GH family 12 (GH12), could be a great threat to many plants because xyloglucan is a major component of the cell wall in most plants. Understanding the inhibition mechanism of XEG by GHIP is therefore of great importance in the field of plant defense, but to date the mechanism and specificity of GHIPs remain unclear. We have determined the crystal structure of XEG in complex with extracellular dermal glycoprotein (EDGP), a carrot GHIP that inhibits XEG. The structure reveals that the conserved arginines of EDGP intrude into the active site of XEG and interact with the catalytic glutamates of the enzyme. We have also determined the crystal structure of the XEG-xyloglucan complex. These structures show that EDGP closely mimics the XEG-xyloglucan interaction. Although EDGP shares structural similarity to a wheat GHIP (Triticum aestivum xylanase inhibitor-IA (TAXI-IA)) that inhibits GH11 family xylanases, the arrangement of GH and GHIP in the XEG-EDGP complex is distinct from that in the xylanase-TAXI-IA complex. Our findings imply that plants have evolved structures of GHIPs to inhibit different GH family members that attack their cell walls.

PubMed: 22496365
DOI: 10.1074/jbc.M112.350520

Experimental method

X-RAY DIFFRACTION (0.95 Å)