Figure 1: Labeled Tubulin-Alexa Fluor® 488 is commonly visualized with a FITC filter set. Left, GMPCPP-stabilized microtubules at 2 mg/ml [tubulin] with Labeled Tubulin-Alexa Fluor® 488 (Cat. No. 048805) and Cycled Tubulin™ (Cat. No. 032005) at a 1:10 ratio. Right, taxol-stabilized microtubules at 5 mg/ml [tubulin] with Labeled Tubulin-Alexa Fluor® 488 (Cat. No. 048805) and Cycled Tubulin™ (Cat. No. 032005) at a 1:10 ratio. Images acquired on a widefield fluorescence microscope.
Figure 2: Labeled Tubulin-Alexa Fluor® 488 displays maximum absorption at 280 nm and 494 nm. Spectroscopic analysis reveals a peak at 280 nm and 494 nm, indicating absorption by tubulin and Alexa Fluor® 488, respectively.
LABELED TUBULIN-ALEXA FLUOR® 488
Catalog Number: 048805
Source: Bovine Brain
Material Labeled Tubulin-Alexa Fluor® 488 is commonly visualized with a FITC filter set with maximum excitation/emission wavelengths of 494/517 nm (Figure 1). The labeled tubulin is generated by reacting Alexa Fluor® 488 succinimidyl ester (Thermo Fisher A20100) with Cycled Tubulin™ (Cat. No. 032005), thereby covalently linking the dye to random tubulin surface lysines. Cycled Tubulin™ is >99% pure and polymerization competent. These properties are maintained during the labeling process by reacting Cycled Tubulin™ with the dye in its polymerized form and subjecting it to a final polymerization/depolymerization cycle. The final product displays maximum absorption at 280 nm and 494 nm, and a labeling stoichiometry ([dye]/[tubulin]) of 0.5-2.0 as determined by spectroscopic analysis (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-Alexa Fluor® 488 will polymerize into microtubules when supplemented with GTP, warmed to 37˚C, and kept above its critical concentration. Labeled tubulin is suitable for use in a variety of fluorescent experimental applications including live cell injection, and can be combined with unlabeled tubulin (Cycled Tubulin | Cat. No. 032005) in generating fluorescent microtubules in vitro. 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.
- in vitro microtubule gliding assays
- single molecule kinesin and dynein motor assays
- speckle microscopy
- live cell injection
- in vitro nanoscale devices
- TIRF, STORM, SIM, STED, TPE, confocal, and widefield microscopy