title: Membrane-associated, boron-interacting proteins isolated by boronate affinity chromatography.
abstract: Boron deficiency symptoms point to a role for boron in plant membranes, but the molecular partners interacting with boron have not yet been identified. The objective of the present study was to isolate and identify membrane-associated proteins with an ability to interact with boron. Boron-interacting proteins were isolated from root microsomal preparations of arabidopsis (Arabidopsis thaliana) and maize (Zea mays) using phenylboronate affinity chromatography, subsequently separated by two-dimensional gel electrophoresis and identified using MALDI-TOF (matrix-assisted laser desorption ionization-time of flight) peptide mass fingerprinting. Twenty-six boron-binding membrane-associated proteins were identified in A. thaliana, and nine in Z. mays roots. Additional unidentified proteins were also present. Common to both species were the beta-subunit of mitochondrial ATP synthase, several beta-glucosidases, a luminal-binding protein and fructose bisphosphate aldolase. In A. thaliana, binding of these proteins to boron was significantly reduced after 4 d of boron deprivation. The relatively high number of diverse proteins identified as boron interacting, many of which are usually enriched in membrane microdomains, supports the hypothesis that boron plays a role in plant membranes by cross-linking glycoproteins, and may be involved in their recruitment to membrane microdomains.
authors.affiliation: Institute of Crop Science and Resource Conservation, University of Bonn, Bonn, Germany. m.wimmer@uni-bonn.de
authors.forename: Monika A
authors.initials: MA
authors.lastname: Wimmer
authors.forename: Günter
authors.initials: G
authors.lastname: Lochnit
authors.forename: Elias
authors.initials: E
authors.lastname: Bassil
authors.forename: Karl H
authors.initials: KH
authors.lastname: Mühling
authors.forename: Heiner E
authors.initials: HE
authors.lastname: Goldbach
mesh_terms: D017360:Arabidopsis / Q000378:metabolism; D001895:Boron / Q000378:metabolism*; D002846:Chromatography, Affinity; D015180:Electrophoresis, Gel, Two-Dimensional; D008565:Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism*; D010940:Plant Proteins / Q000302:isolation & purification / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism*; D040901:Proteomics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D003313:Zea mays / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D010940:Plant Proteins; D001895:Boron