RRC ID 48575
Author Hocq L, Sénéchal F, Lefebvre V, Lehner A, Domon JM, Mollet JC, Dehors J, Pageau K, Marcelo P, Guérineau F, Kolšek K, Mercadante D, Pelloux J.
Title Combined Experimental and Computational Approaches Reveal Distinct pH Dependence of Pectin Methylesterase Inhibitors.
Journal Plant Physiol
Abstract The fine-tuning of the degree of methylesterification of cell wall pectin is a key to regulating cell elongation and ultimately the shape of the plant body. Pectin methylesterification is spatiotemporally controlled by pectin methylesterases (PMEs; 66 members in Arabidopsis [Arabidopsis thaliana]). The comparably large number of proteinaceous pectin methylesterase inhibitors (PMEIs; 76 members in Arabidopsis) questions the specificity of the PME-PMEI interaction and the functional role of such abundance. To understand the difference, or redundancy, between PMEIs, we used molecular dynamics (MD) simulations to predict the behavior of two PMEIs that are coexpressed and have distinct effects on plant development: AtPMEI4 and AtPMEI9. Simulations revealed the structural determinants of the pH dependence for the interaction of these inhibitors with AtPME3, a major PME expressed in roots. Key residues that are likely to play a role in the pH dependence were identified. The predictions obtained from MD simulations were confirmed in vitro, showing that AtPMEI9 is a stronger, less pH-independent inhibitor compared with AtPMEI4. Using pollen tubes as a developmental model, we showed that these biochemical differences have a biological significance. Application of purified proteins at pH ranges in which PMEI inhibition differed between AtPMEI4 and AtPMEI9 had distinct consequences on pollen tube elongation. Therefore, MD simulations have proven to be a powerful tool to predict functional diversity between PMEIs, allowing the discovery of a strategy that may be used by PMEIs to inhibit PMEs in different microenvironmental conditions and paving the way to identify the specific role of PMEI diversity in muro.
Volume 173(2)
Pages 1075-1093
Published 2017-2-1
DOI 10.1104/pp.16.01790
PII pp.16.01790
PMID 28034952
PMC PMC5291010
MeSH Arabidopsis / metabolism* Arabidopsis Proteins / genetics Arabidopsis Proteins / metabolism* Carboxylic Ester Hydrolases / antagonists & inhibitors* Carboxylic Ester Hydrolases / metabolism* Cell Wall / metabolism Computational Biology / methods* Enzyme Inhibitors / metabolism* Escherichia coli / metabolism Gene Expression Regulation, Plant Germination Hydrogen Bonding Hydrogen-Ion Concentration Hypocotyl / growth & development Hypocotyl / metabolism Molecular Dynamics Simulation Plant Roots / growth & development Plant Roots / metabolism Pollen Tube / growth & development Pollen Tube / metabolism Recombinant Proteins / metabolism
IF 6.305
Times Cited 11
Arabidopsis / Cultured plant cells, genes pda18258