title: A group 6 late embryogenesis abundant protein from common bean is a disordered protein with extended helical structure and oligomer-forming properties.
abstract: Late embryogenesis-abundant proteins accumulate to high levels in dry seeds. Some of them also accumulate in response to water deficit in vegetative tissues, which leads to a remarkable association between their presence and low water availability conditions. A major sub-group of these proteins, also known as typical LEA proteins, shows high hydrophilicity and a high percentage of glycine and other small amino acid residues, distinctive physicochemical properties that predict a high content of structural disorder. Although all typical LEA proteins share these characteristics, seven groups can be distinguished by sequence similarity, indicating structural and functional diversity among them. Some of these groups have been extensively studied; however, others require a more detailed analysis to advance in their functional understanding. In this work, we report the structural characterization of a group 6 LEA protein from a common bean (Phaseolus vulgaris L.) (PvLEA6) by circular dichroism and nuclear magnetic resonance showing that it is a disordered protein in aqueous solution. Using the same techniques, we show that despite its unstructured nature, the addition of trifluoroethanol exhibited an intrinsic potential in this protein to gain helicity. This property was also promoted by high osmotic potentials or molecular crowding. Furthermore, we demonstrate that PvLEA6 protein is able to form soluble homo-oligomeric complexes that also show high levels of structural disorder. The association between PvLEA6 monomers to form dimers was shown to occur in plant cells by bimolecular fluorescence complementation, pointing to the in vivo functional relevance of this association.
authors.affiliation: Departamentos de Biología Molecular de Plantas and Universidad Nacional Autónoma de México, Apdo. Postal 510-3, 62250 Cuernavaca, Mor.
authors.forename: Lucero Y
authors.initials: LY
authors.lastname: Rivera-Najera
authors.affiliation: Departamentos de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, 62250 Cuernavaca, Mor.
authors.forename: Gloria
authors.initials: G
authors.lastname: Saab-Rincón
authors.affiliation: Departamentos de Biología Molecular de Plantas and Universidad Nacional Autónoma de México, Apdo. Postal 510-3, 62250 Cuernavaca, Mor.
authors.forename: Marina
authors.initials: M
authors.lastname: Battaglia
authors.affiliation: Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Av. Universidad No. 1001, Col Chamilpa, 62209 Cuernavaca, Morelos, and.
authors.forename: Carlos
authors.initials: C
authors.lastname: Amero
authors.affiliation: Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México 04510, D. F. México.
authors.forename: Nancy O
authors.initials: NO
authors.lastname: Pulido
authors.affiliation: Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México 04510, D. F. México.
authors.forename: Enrique
authors.initials: E
authors.lastname: García-Hernández
authors.affiliation: Departamentos de Biología Molecular de Plantas and Universidad Nacional Autónoma de México, Apdo. Postal 510-3, 62250 Cuernavaca, Mor.
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Solórzano
authors.affiliation: Departamentos de Biología Molecular de Plantas and Universidad Nacional Autónoma de México, Apdo. Postal 510-3, 62250 Cuernavaca, Mor.
authors.forename: José L
authors.initials: JL
authors.lastname: Reyes
authors.affiliation: Departamentos de Biología Molecular de Plantas and Universidad Nacional Autónoma de México, Apdo. Postal 510-3, 62250 Cuernavaca, Mor.. Electronic address: crobles@ibt.unam.mx.
authors.forename: Alejandra A
authors.initials: AA
authors.lastname: Covarrubias
mesh_terms: D000595:Amino Acid Sequence; D002151:Calorimetry; D002850:Chromatography, Gel; D002942:Circular Dichroism; D003432:Cross-Linking Reagents / Q000737:chemistry; D005470:Fluorometry; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009994:Osmolar Concentration; D027805:Phaseolus / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry*; D011485:Protein Binding; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D014867:Water / Q000737:chemistry
chemical_list: D003432:Cross-Linking Reagents; D010940:Plant Proteins; D011994:Recombinant Proteins; C066246:late embryogenesis abundant protein, plant; D014867:Water
keywords: Intrinsically Disordered Protein; Isothermal Titration Calorimetry (ITC); Plant Biology; Protein Conformation; Protein Self-assembly; Protein Structure; Stress Response