Structure of a lectin from Canavalia gladiata seeds: new structural insights for old moleculesReport as inadecuate




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BMC Structural Biology

, 7:52

First Online: 02 August 2007Received: 06 October 2006Accepted: 02 August 2007

Abstract

BackgroundLectins are mainly described as simple carbohydrate-binding proteins. Previous studies have tried to identify other binding sites, which possible recognize plant hormones, secondary metabolites, and isolated amino acid residues. We report the crystal structure of a lectin isolated from Canavalia gladiata seeds CGL, describing a new binding pocket, which may be related to pathogen resistance activity in ConA-like lectins; a site where a non-protein amino-acid, α-aminobutyric acid Abu, is bound.

ResultsThe overall structure of native CGL and complexed with α-methyl-mannoside and Abu have been refined at 2.3 Å and 2.31 Å resolution, respectively. Analysis of the electron density maps of the CGL structure shows clearly the presence of Abu, which was confirmed by mass spectrometry.

ConclusionThe presence of Abu in a plant lectin structure strongly indicates the ability of lectins on carrying secondary metabolites. Comparison of the amino acids composing the site with other legume lectins revealed that this site is conserved, providing an evidence of the biological relevance of this site. This new action of lectins strengthens their role in defense mechanisms in plants.

Abbreviations usedAbuα-aminobutyric acid

CGLCanavalia gladiata lectin

HRHypersensitive response

CGL-αMMCanavalia gladiata lectin in complex with α-methyl-mannoside

ConACanavalia ensiformis lectin

ESIElectrospray ionization source

Q-ToFQuadrupole-time of flight analyzer

SARsystemic acquired resistance

ISRinduced systemic resistance.

Electronic supplementary materialThe online version of this article doi:10.1186-1472-6807-7-52 contains supplementary material, which is available to authorized users.

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Author: Plínio Delatorre - Bruno AM Rocha - Emmanuel P Souza - Taianá M Oliveira - Gustavo A Bezerra - Frederico BMB Moreno -

Source: https://link.springer.com/







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