Signaling Through Scaffold, Anchoring, and adaptor proteins

Signaling Through Scaffold, Anchoring, and adaptor proteins

(Parte 3 de 3)

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Cancer Institute of Canada and J.D.S. is supported by NIH grant GM48231. We thank R. Frank for technical assistance. Because of space limitations, we were not able to acknowledge the contributions of all investigators to this growing field.

Large-Cage Zeolite Structures with Multidimensional

12-Ring Channels

Xianhui Bu, Pingyun Feng, Galen D. Stucky

Zeolite type structures with large cages interconnected by multidimensional 12-ring (rings of 12 tetrahedrally coordinated atoms) channels have been synthesized; more than a dozen large-pore materials were created in three different topologies with aluminum (or gallium), cobalt (or manganese, magnesium, or zinc), and phosphorus at the tetrahedral coordination sites. Tetragonal UCSB-8 has an unusually large cage built from 64 tetrahedral atoms and connected by an orthogonal channel system with 12-ring apertures in two dimensions and 8-ring apertures in the third. Rhombohedral UCSB-10 and hexagonal UCSB-6 are structurally related to faujasite and its hexagonal polymorph, respectively, and have large cages connected by 12-ring channels in all three dimensions.

Extensive research has led to the synthesis of zeolitic materials with previously unseen compositions and framework topologies (1), including ultralarge-pore structures VPI-5, ly (2). A number of structures with 12-ring channels (for example, AlPO4-5, MAPSO- 46, and CoAPO-50) have also been report- ed (1). Other open framework structures that have large cages or pore sizes include JDF-20, cloverite (3), and unusually lowdensity vanadium phosphate frameworks (4).

Unlike faujasite or its hexagonal polymorph, known materials with a zeolite

X. Bu and P. Feng are in the Department of Chemistry and G. D. Stucky is in the Department of Chemistry and Department of Materials, University of California, Santa Barbara, CA 93106, USA.

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