TY - JOUR
T1 - Heterogeneous and homogeneous nucleation of Taxol™ crystals in aqueous solutions and gels
T2 - Effect of tubulin proteins
AU - Castro, Javier S.
AU - Deymier, Pierre A.
AU - Trzaskowski, Bartosz
AU - Bucay, Jaim
N1 - Funding Information:
We acknowledge financial support from NSF/NIRT Grant 0303863 .
PY - 2010/3/1
Y1 - 2010/3/1
N2 - In this study we report crystallization of Taxol in pure water, aqueous solutions containing tubulin proteins and tubulin-containing agarose gels. We show that crystallization of Taxol in tubulin-free aqueous solutions occurs by the formation of sheaf-like crystals, while in the presence of tubulin Taxol crystallizes in the form of spherulites. Whereas sheaves are characteristic for crystals formed by homogeneous nucleation, the spherical symmetry of the Taxol crystal formed in the presence of tubulin suggests they result from heterogeneous nucleation. To explain the formation of tubulin-Taxol nuclei we suggest a new, secondary Taxol-binding site within the tubulin heterodimer. Contrary to the known binding site, where the Taxol molecule is almost completely buried in the protein, the Taxol molecule in the secondary binding site is partially exposed to the solution and may serve as a bridge, connecting other Taxol molecules. Results presented in this work are important for in vivo and in vitro microtubule studies due to the possibility of mistaking these Taxol spherulites for microtubule asters, moreover a novel variable is proposed in the study of cells treated with Taxol for cancer treatment via sequestration of tubulin.
AB - In this study we report crystallization of Taxol in pure water, aqueous solutions containing tubulin proteins and tubulin-containing agarose gels. We show that crystallization of Taxol in tubulin-free aqueous solutions occurs by the formation of sheaf-like crystals, while in the presence of tubulin Taxol crystallizes in the form of spherulites. Whereas sheaves are characteristic for crystals formed by homogeneous nucleation, the spherical symmetry of the Taxol crystal formed in the presence of tubulin suggests they result from heterogeneous nucleation. To explain the formation of tubulin-Taxol nuclei we suggest a new, secondary Taxol-binding site within the tubulin heterodimer. Contrary to the known binding site, where the Taxol molecule is almost completely buried in the protein, the Taxol molecule in the secondary binding site is partially exposed to the solution and may serve as a bridge, connecting other Taxol molecules. Results presented in this work are important for in vivo and in vitro microtubule studies due to the possibility of mistaking these Taxol spherulites for microtubule asters, moreover a novel variable is proposed in the study of cells treated with Taxol for cancer treatment via sequestration of tubulin.
KW - Crystals
KW - Microtubule aster
KW - Nucleation
KW - Paclitaxel
KW - Spherulites
KW - Taxol
KW - Tubulin
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U2 - 10.1016/j.colsurfb.2009.10.033
DO - 10.1016/j.colsurfb.2009.10.033
M3 - Article
C2 - 19945829
AN - SCOPUS:74249100399
VL - 76
SP - 199
EP - 206
JO - Colloids and Surfaces B: Biointerfaces
JF - Colloids and Surfaces B: Biointerfaces
SN - 0927-7765
IS - 1
ER -