Ligand-induced conformational changes via flexible linkers in the amino-terminal region of the inositol 1,4,5-trisphosphate receptor.

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dc.contributor.authorChan, Jen_AU
dc.contributor.authorWhitten, AEen_AU
dc.contributor.authorJeffries, CMen_AU
dc.contributor.authorBosanac, Ien_AU
dc.contributor.authorMal, TKen_AU
dc.contributor.authorIto, Jen_AU
dc.contributor.authorPorumb, Hen_AU
dc.contributor.authorMichikawa, Ten_AU
dc.contributor.authorMikoshiba, Ken_AU
dc.contributor.authorTrewhella, Jen_AU
dc.contributor.authorIkura, Men_AU
dc.date.accessioned2008-04-18T04:23:05Zen_AU
dc.date.accessioned2010-04-30T05:02:37Zen_AU
dc.date.available2008-04-18T04:23:05Zen_AU
dc.date.available2010-04-30T05:02:37Zen_AU
dc.date.issued2007-11-09en_AU
dc.date.statistics2007-11en_AU
dc.description.abstractCytoplasmic Ca2+ signals are highly regulated by various ion transporters, including the inositol 1,4,5-trisphosphate (IP3) receptor (IP3), which functions as a Ca2+ release channel on the endoplasmic reticulum membrane. Crystal structures of the two N-terminal regulatory regions from type 1 IP3R have been reported; those of the IP3-binding core (IP3RCORE) with bound IP3, and the suppressor domain. This study examines the structural effects of ligand binding on an IP3R construct, designated IP3RN, that contains both the IP3-binding core and the suppressor domain. Our circular dichroism results reveal that the IP3- bound and IP3-free states have similar secondary structure content, consistent with preservation of the overall fold within the individual domains. Thermal denaturation data show that, while IP3 has a large effect on the stability of IP3RCORE, it has little effect on IP3RN, indicating that the suppressor domain is critical to the stability of IP3RN. The NMR data for IP3RN provide evidence for chemical exchange, which may be due to protein conformational dynamics in both apo and IP3-bound states: a conclusion supported by the small-angle X-ray scattering data. Further, the scattering data show that IP3RN undergoes a change m average conformation in response to IP3-binding and the presence of Ca2+, in the solution. Taken together, these data lead us to propose that there are two flexible linkers in the N-terminal region of lP(3)R that join stably folded domains and give rise to an equilibrium mixture of conformational sub-states containing compact and more extended structures. IP3 binding drives the conformational equilibrium toward more compact structures, while the presence of Ca2+ drives it to a more extended set. © 2007, Elsevier Ltd.en_AU
dc.identifier.citationChan, J., Whitten, A. E., Jeffries, C. M., Bosanac, I., Mal, T. K., Ito, J., Porumb, H., Michikawa, T., Mikoshiba, K., Trewella, J., & Ikura, M. (2007). Ligand-induced conformational changes via flexible linkers in the amino-terminal region of the inositol 1,4,5-trisphosphate receptor. Journal of Molecular Biology, 373(5), 1269-1280. doi:10.1016/j.jmb.2007.08.057en_AU
dc.identifier.govdoc1164en_AU
dc.identifier.issn0022-2836en_AU
dc.identifier.issue5en_AU
dc.identifier.journaltitleJournal of Molecular Biologyen_AU
dc.identifier.pagination1269-1280en_AU
dc.identifier.urihttp://dx.doi.org/10.1016/j.jmb.2007.08.057en_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/1074en_AU
dc.identifier.volume373en_AU
dc.language.isoenen_AU
dc.publisherElsevieren_AU
dc.subjectMagnetic circular dichroismen_AU
dc.subjectNuclear magnetic resonanceen_AU
dc.subjectSmall angle scatteringen_AU
dc.subjectSimulationen_AU
dc.subjectReceptorsen_AU
dc.subjectCalciumen_AU
dc.titleLigand-induced conformational changes via flexible linkers in the amino-terminal region of the inositol 1,4,5-trisphosphate receptor.en_AU
dc.typeJournal Articleen_AU
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