Catalog Number: 033305
Molecular Weight: ~110 kDa
Labeling Stoichiometry: ~4.0 (check product label)
Form: clear aqueous solution
Concentration: 20 mg/ml
Buffer Conditions: 50 mM K-Glutamate and 0.5 mM MgCl2 (pH 7.0)
Shipping: shipped on dry ice
Storage Conditions: store at -80˚C immediately
Shelf Life: check product label for expiration date
Fluorescent image of biotinylated microtubules incubated in a streptavidin-coated flow cells. Microtubules were polymerized at 2 mg/ml total tubulin protein with Labeled Tubulin-Biotin-XX (Cat. No. 033305), Labeled Tubulin-Alexa Fluor® 647 (064705), and Cycled Tubulin™ (Cat. No. 032005) at a 0.5:1:10 ratio and stabilized with GMPCPP.
Labeled Tubulin-Biotin-XX is generated by reacting Biotin-XX succinimidyl ester with >99% pure tubulin protein, thereby covalently linking the biomolecule to random tubulin surface lysines. Polymerization competency is maintained during the labeling process by reacting the tubulin protein with the reactive biotin in its polymerized form and subjecting it to a final polymerization/depolymerization cycle. The final labeled tubulin protein demonstrates an affinity toward streptavidin-coated beads (Figure 1) and streptavidin-coated coverslips (Figure 2). Specific labeling stoichiometries are indicated on the product label. The product is cryopreserved at 20 mg/ml in 50 mM K-Glutamate and 0.5 mM MgCl2 (pH=7.0).
Activity and Applications
Labeled Tubulin-Biotin-XX will polymerize into microtubules when supplemented with GTP, warmed to 37˚C, and kept above its critical concentration. Polymerization activity is detectable in a variety of experimental systems including fluorescence microscopy assays, turbidity assays, and GTPase assays. Biotinylated tubulin is suitable for use in a variety of experimental applications, and can be combined with other labeled or unlabeled tubulin proteins in generating microtubules in vitro. Cycled Tubulin™ (Cat. No. 032005) is highly recommended as the unlabeled tubulin protein source in order to minimize tubulin heterogeneity, as labeled tubulin reagents are derived directly from Cycled Tubulin™. Visit our protocols page for common microtubule polymerization protocols, including the generation of short, rigid microtubules stabilized by GMPCPP or long, flexible microtubules stabilized by taxol.
- optical traps and molecular tweezers
- single molecule kinesin and dynein motor assays
- tubulin affinity columns
- in vitro nanoscale devices
Tubulin Protein With A Strong Affinity For Streptavidin
Labeled Tubulin-Biotin-XX binds to streptavidin-coated beads. Coomassie G250-stained protein gel of unbound and bound fractions of tubulin protein samples incubated with Dynabeads® M-280 Streptavidin (Thermo Fisher 11205D). Cycled Tubulin serves as the non-biotinylated negative control. Labeled Tubulin-Biotin-XX fractionates with the streptavidin-coated beads.
Labeled Tubulin-Biotin-XX binds to streptavidin-coated coverslips. Fluorescent images of microtubules incubated in streptavidin-coated flow cells. Microtubules were polymerized at 2 mg/ml total tubulin protein with Labeled Tubulin-Biotin-XX (Cat. No. 033305), Labeled Tubulin-Alexa Fluor® 647 (064705), and Cycled Tubulin™ (Cat. No. 032005) at a 0.5:1:10 ratio and stabilized with GMPCPP. Images acquired on a widefield fluorescence microscope.