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EMBO J. 2002 Jul 15;21(14):3575-81.

Three-dimensional structure of the type 1 inositol 1,4,5-trisphosphate receptor at 24 A resolution.

Author information

1
Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA. jiangq@cmp.yale.edu

Abstract

We report here the first three-dimensional structure of the type 1 inositol 1,4,5-trisphosphate receptor (IP(3)R). From cryo-electron microscopic images of purified receptors embedded in vitreous ice, a three-dimensional structure was determined by use of standard single particle reconstruction techniques. The structure is strikingly different from that of the ryanodine receptor at similar resolution despite molecular similarities between these two calcium release channels. The 24 A resolution structure of the IP(3)R takes the shape of an uneven dumbbell, and is approximately 170 A tall. Its larger end is bulky, with four arms protruding laterally by approximately 50 A and, in comparison with the receptor topology, probably corresponds to the cytoplasmic domain of the receptor. The lateral dimension at the height of the protruding arms is approximately 155 A. The smaller end, whose lateral dimension is approximately 100 A, has structural features indicative of the membrane-spanning domain. A central opening in this domain, which is occluded on the cytoplasmic half, outlines a pathway for calcium flow in the open state of the channel.

PMID:
12110570
PMCID:
PMC126125
DOI:
10.1093/emboj/cdf380
[Indexed for MEDLINE]
Free PMC Article
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