title: Aspen SP1, an exceptional thermal, protease and detergent-resistant self-assembled nano-particle.
abstract: Stable protein 1 (SP1) is a homo-oligomeric protein isolated from aspen (Populus tremula aspen) plants which forms a ring-shape dodecameric particle with a central cavity. The oligomeric form of SP1 is an exceptionally stable structure that is resistant to proteases (e.g., trypsin, V8, and proteinase K), high temperatures, organic solvents, and high levels of ionic detergent. Analytical ultra-centrifugation, chemical cross-linking, matrix-assisted laser-desorption time-of-flight mass spectrometry (MALDI-TOF-MS), and transmission electron microscopy were used to further characterize the SP1 dodecamer. Introduction of a single cysteine at the N-terminus of SP1 enabled the formation of disulfide bridges within the SP1 dodecamer, concurrent with increased melting point. A six-histidine tag was introduced at the N-terminus of SP1 to generate 6HSP1, and the DeltaNSP1 mutant was generated by a deletion of amino acids 2-6 at the N-terminus. Both 6HSP1 and DeltaNSP1 maintained their ability to assemble a stable dodecamer. Remarkably, these SP1 homo-dodecamers were able to re-assemble into stable hetero-dodecamers following co-electro-elution from SDS-PAGE. The exceptional stability of the SP1-nano ring and its ability to self-assemble hetero-complexes paves the way to further research in utilizing this unique protein in nano-biotechnology.
authors.affiliation: The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, and the Otto Warburg Center for Agricultural Biotechnology, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Israel.
authors.forename: Wang-Xia
authors.initials: WX
authors.lastname: Wang
authors.forename: Or
authors.initials: O
authors.lastname: Dgany
authors.forename: Sharon Grayer
authors.initials: SG
authors.lastname: Wolf
authors.forename: Ilan
authors.initials: I
authors.lastname: Levy
authors.forename: Rachel
authors.initials: R
authors.lastname: Algom
authors.forename: Yehonathan
authors.initials: Y
authors.lastname: Pouny
authors.forename: Amnon
authors.initials: A
authors.lastname: Wolf
authors.forename: Ira
authors.initials: I
authors.lastname: Marton
authors.forename: Arie
authors.initials: A
authors.lastname: Altman
authors.forename: Oded
authors.initials: O
authors.lastname: Shoseyov
mesh_terms: D003460:Crystallization / Q000379:methods*; D003902:Detergents / Q000737:chemistry*; D019281:Dimerization; D004789:Enzyme Activation; D004795:Enzyme Stability; D046912:Multiprotein Complexes / Q000032:analysis / Q000737:chemistry / Q000648:ultrastructure; D049329:Nanostructures / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure*; D010940:Plant Proteins / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure*; D032107:Populus / Q000201:enzymology*; D011485:Protein Binding; D013696:Temperature
chemical_list: D003902:Detergents; D046912:Multiprotein Complexes; D010940:Plant Proteins