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Gachomo E.W.,Rutgers University | Jimenez-Lopez J.C.,High Council for Scientific Research CSIC | Kayode A.P.P.,University Abomey Calavi | Baba-Moussa L.,University Abomey Calavi | Kotchoni S.O.,Rutgers University
Molecular Biology Reports | Year: 2012

Plant defensins represent a major innate immune protein superfamily with strong inhibitory effects on infectious diseases of humans, antifungal/ antibacterial activities, proteinase and insect amylase inhibitory activities. They are generally defined by their conserved cysteine scaffold with α-helix and triple strand anti parallel β-sheet connected to the scaffold. With the genome of more plant species being fully sequenced, significant information about newly sequenced defensin proteins has been revealed. In this paper, we identify members of defensin protein families across plant species and use protein-modeling-based structural reconstitution to reveal specific three dimensional hidden features of plant defensins mediating defense responses and other interesting biological activities in plants. Our data revealed that plant defensins are structurally similar to their insect counterparts despite the low amino acid sequence similarity between these two organisms. The molecular and structural relationship among plant defensins and defensins from other species is discussed. © Springer Science+Business Media B.V. 2011.

Jimenez-Lopez J.C.,Purdue University | Jimenez-Lopez J.C.,High Council for Scientific Research CSIC | Kotchoni S.O.,Rutgers University | Rodriguez-Garcia M.I.,High Council for Scientific Research CSIC | Alche J.D.,High Council for Scientific Research CSIC
Journal of Molecular Modeling | Year: 2012

Pectin methylesterases (PMEs), a multigene family of proteins with multiple differentially regulated isoforms, are key enzymes implicated in the carbohydrates (pectin) metabolism of cell walls. Olive pollen PME has been identified as a new allergen (Ole e 11) of potential relevance in allergy amelioration, since it exhibits high prevalence among atopic patients. In this work, the structural and functional characterization of two olive pollen PME isoforms and their comparison with other PME plants was performed by using different approaches: (1) the physicochemical properties and functional-regulatory motifs characterization, (2) primary sequence analysis, 2D and 3D comparative structural features study, (3) conservation and evolutionary analysis, (4) catalytic activity and regulation based on molecular docking analysis of a homologue PME inhibitor, and (5) B-cell epitopes prediction by sequence and structural based methods and protein-protein interaction tools, while T-cell epitopes by inhibitory concentration and binding score methods. Our results indicate that the structural differences and low conservation of residues, together with differences in physicochemical and posttranslational motifs might be a mechanism for PME isovariants generation, regulation, and differential surface epitopes generation. Olive PMEs perform a processive catalytic mechanism, and a differential molecular interaction with specific PME inhibitor, opening new possibilities for PME activity regulation. Despite the common function of PMEs, differential features found in this study will lead to a better understanding of the structural and functional characterization of plant PMEs and help to improve the componentresolving diagnosis and immunotherapy of olive pollen allergy by epitopes identification. © Springer-Verlag 2012.

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