The native structure and composition of the cruciferin complex in brassica napus
Creators: name: Nietzel, Thomas
name: Dudkina, Natalya V.
name: Haase, Christin
name: Denolf, Peter
name: Semchonok, Dmitry A.
name: Boekema, Egbert J.
name: Braun, Hans-Peter
name: Sunderhaus, Stephanie
Publisher: name: Bethesda, Md. : ASBMB Publications
Year: 2013
Subjects: subject: Brassica napus
subject: Building blockes
subject: Dicotyledonous plants
subject: Differential centrifugation
subject: Isoelectric focusing
subject: Isoforms
subject: Native structures
subject: Plant species
subject: Polypeptide chain
subject: Post-translational modifications
subject: Projection maps
subject: Protein analysis
subject: Protein complexes
subject: Protein storage vacuole
subject: Seed development
subject: Seed storage proteins
subject: Single particle
subject: Amino acids
subject: Electron microscopy
subject: Electrophoresis
subject: Mass spectrometry
subject: Proteins
subject: Seed
subject: Two dimensional
subject: Biosynthesis
subject: cruciferin
subject: isoprotein
subject: mitochondrial protein
subject: unclassified drug
subject: vegetable protein
subject: alpha chain
subject: amino terminal sequence
subject: Arabidopsis
subject: article
subject: beta chain
subject: carboxy terminal sequence
subject: complex formation
subject: controlled study
subject: electron microscopy
subject: isoelectric focusing
subject: mass spectrometry
subject: molecular weight
subject: nonhuman
subject: plant seed
subject: polyacrylamide gel electrophoresis
subject: priority journal
subject: protein analysis
subject: protein expression
subject: protein phosphorylation
subject: protein processing
subject: rapeseed
subject: structural proteomics
subject: structure analysis
subject: Amino Acids
subject: Antigens, Plant
subject: Electrophoresis, Polyacrylamide Gel
subject: Isoelectric Focusing
subject: Microscopy, Electron
subject: Peptides
subject: Plant Physiological Phenomena
subject: Plant Proteins
subject: Protein Conformation
subject: Protein Isoforms
subject: Protein Structure, Tertiary
subject: Proteomics
subject: Seed Storage Proteins
subject: Seeds
subject: Vacuoles
subject: Dewey Decimal Classification::500 | Naturwissenschaften::570 | Biowissenschaften, Biologie
subject: Dewey Decimal Classification::500 | Naturwissenschaften::540 | Chemie

description: Globulins are an important group of seed storage proteins in dicotyledonous plants. They are synthesized during seed development, assembled into very compact protein complexes, and finally stored in protein storage vacuoles (PSVs). Here, we report a proteomic investigation on the native composition and structure of cruciferin, the 12 S globulin of Brassica napus. PSVs were directly purified from mature seeds by differential centrifugations. Upon analyses by blue native (BN) PAGE, two major types of cruciferin complexes of ~ 300-390 kDa and of ~470 kDa are resolved. Analyses by two-dimensional BN/SDS-PAGE revealed that both types of complexes are composed of several copies of the cruciferin α and β polypeptide chains, which are present in various isoforms. Protein analyses by two-dimensional isoelectric focusing (IEF)/SDS-PAGE not only revealed different α and β isoforms but also several further versions of the two polypeptide chains that most likely differ with respect to posttranslational modifications. Overall, more than 30 distinct forms of cruciferin were identified by mass spectrometry. To obtain insights into the structure of the cruciferin holocomplex, a native PSV fraction was analyzed by single particle electron microscopy. More than 20,000 images were collected, classified, and used for the calculation of detailed projection maps of the complex. In contrast to previous reports on globulin structure in other plant species, the cruciferin complex of Brassica napus has an octameric barrel-like structure, which represents a very compact building block optimized for maximal storage of amino acids within minimal space.