3R50

Structure analysis of a wound-inducible lectin ipomoelin from sweet potato

Summary for 3R50

• Entry DOI: 10.2210/pdb3r50/pdb
• Related: 3R51 3R52 3R53
• Descriptor: Ipomoelin (2 entities in total)
• Functional Keywords: beta prism, carbohydrate/sugar binding, carbohydrate-binding protein
• Biological source: Ipomoea batatas (batate)
• Total number of polymer chains: 5
• Total formula weight: 86727.10

Authors

Liu, K.L.,Chang, W.C.,Jeng, S.T.,Cheng, Y.S. (deposition date: 2011-03-18, release date: 2012-03-28, Last modification date: 2023-09-13)

Primary citation

Chang, W.C.,Liu, K.L.,Hsu, F.C.,Jeng, S.T.,Cheng, Y.S.
Ipomoelin, a jacalin-related lectin with a compact tetrameric association and versatile carbohydrate binding properties regulated by its N terminus.
Plos One, 7:e40618-e40618, 2012

PubMed Abstract: Many proteins are induced in the plant defense response to biotic stress or mechanical wounding. One group is lectins. Ipomoelin (IPO) is one of the wound-inducible proteins of sweet potato (Ipomoea batatas cv. Tainung 57) and is a Jacalin-related lectin (JRL). In this study, we resolved the crystal structures of IPO in its apo form and in complex with carbohydrates such as methyl α-D-mannopyranoside (Me-Man), methyl α-D-glucopyranoside (Me-Glc), and methyl α-D-galactopyranoside (Me-Gal) in different space groups. The packing diagrams indicated that IPO might represent a compact tetrameric association in the JRL family. The protomer of IPO showed a canonical β-prism fold with 12 strands of β-sheets but with 2 additional short β-strands at the N terminus. A truncated IPO (ΔN10IPO) by removing the 2 short β-strands of the N terminus was used to reveal its role in a tetrameric association. Gel filtration chromatography confirmed IPO as a tetrameric form in solution. Isothermal titration calorimetry determined the binding constants (K(A)) of IPO and ΔN10IPO against various carbohydrates. IPO could bind to Me-Man, Me-Glc, and Me-Gal with similar binding constants. In contrast, ΔN10IPO showed high binding ability to Me-Man and Me-Glc but could not bind to Me-Gal. Our structural and functional analysis of IPO revealed that its compact tetrameric association and carbohydrate binding polyspecificity could be regulated by the 2 additional N-terminal β-strands. The versatile carbohydrate binding properties of IPO might play a role in plant defense.

PubMed: 22808208
DOI: 10.1371/journal.pone.0040618

Experimental method

X-RAY DIFFRACTION (2.27 Å)