dorsal/arxiv
View SchemaMobility of Taxol in Microtubule Bundles
| Authors | Jennifer L. Ross, D. Kuchnir Fygenson |
|---|---|
| Categories | |
| ArXiv ID | q-bio/0309004 |
| URL | https://arxiv.org/abs/q-bio/0309004 |
| DOI | 10.1016/S0006-3495(03)75123-6 |
| Journal | Biophys. J. 2003 84: 3959-3967 |
Abstract
Mobility of taxol inside microtubules was investigated using fluorescence recovery after photobleaching (FRAP) on flow-aligned bundles. Bundles were made of microtubules with either GMPCPP or GTP at the exchangeable site on the tubulin dimer. Recovery times were sensitive to bundle thickness and packing, indicating that taxol molecules are able to move laterally through the bundle. The density of open binding sites along a microtubule was varied by controlling the concentration of taxol in solution for GMPCPP samples. With > 63% sites occupied, recovery times were independent of taxol concentration and, therefore, inversely proportional to the microscopic dissociation rate, k_{off}. It was found that 10*k_{off} (GMPCPP) ~ k_{off} (GTP), consistent with, but not fully accounting for, the difference in equilibrium constants for taxol on GMPCPP and GTP microtubules. With < 63% sites occupied, recovery times decreased as ~ [Tax]^{-1/5} for both types of microtubules. We conclude that the diffusion of taxol along the microtubule interior is hindered by rebinding events when open sites are within ~7 nm of each other.
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"abstract": "Mobility of taxol inside microtubules was investigated using fluorescence\nrecovery after photobleaching (FRAP) on flow-aligned bundles. Bundles were made\nof microtubules with either GMPCPP or GTP at the exchangeable site on the\ntubulin dimer. Recovery times were sensitive to bundle thickness and packing,\nindicating that taxol molecules are able to move laterally through the bundle.\nThe density of open binding sites along a microtubule was varied by controlling\nthe concentration of taxol in solution for GMPCPP samples. With \u003e 63% sites\noccupied, recovery times were independent of taxol concentration and,\ntherefore, inversely proportional to the microscopic dissociation rate,\nk_{off}. It was found that 10*k_{off} (GMPCPP) ~ k_{off} (GTP), consistent\nwith, but not fully accounting for, the difference in equilibrium constants for\ntaxol on GMPCPP and GTP microtubules. With \u003c 63% sites occupied, recovery times\ndecreased as ~ [Tax]^{-1/5} for both types of microtubules. We conclude that\nthe diffusion of taxol along the microtubule interior is hindered by rebinding\nevents when open sites are within ~7 nm of each other.",
"arxiv_id": "q-bio/0309004",
"authors": [
"Jennifer L. Ross",
"D. Kuchnir Fygenson"
],
"categories": [
"q-bio.SC",
"physics.bio-ph"
],
"doi": "10.1016/S0006-3495(03)75123-6",
"journal_ref": "Biophys. J. 2003 84: 3959-3967",
"title": "Mobility of Taxol in Microtubule Bundles",
"url": "https://arxiv.org/abs/q-bio/0309004"
},
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