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Sci. STKE, 3 February 2004
[DOI: 10.1126/stke.2182004re3]

G Protein Signaling: Insights from New Structures
(Conformational Changes Associated with GTP Binding and Hydrolysis)

Anita M. Preininger and Heidi E. Hamm*

1Department of Pharmacology, Vanderbilt University Medical Center, Nashville TN 37232-6600, USA.


*Corresponding author. E-mail: heidi.hamm{at}

Movie. Conformational changes associated with GTP binding and hydrolysis. This movie starts with the inactive guanosine diphosphate (GDP)-bound form of the {alpha} subunit of bovine transducin (G{alpha}t) bound to the βγ subunit shown in grey. In the G{alpha} subunit, the helical domain is shown in red, and the GTPase domain is shown in green. The exchange of GDP for guanosine triphosphate (GTP) is followed by the changes associated with GTPase activity. Upon GTP binding and hydrolysis, regions in yellow color (switch regions) undergo dramatic conformational changes. Note the opening and closing of the switch regions that accompanies the GDP- and GTP-bound states.

The movie was created by Cameron Slayden with the oversight of A. Preininger and H. E. Hamm and is based on crystal structures. The inactive GDP-bound state of G{alpha} is based on PDB file 1TAG, the βγ is based on PDB file 1TBG, the active GTP-bound state is represented by the structure with the nonhydrolyzable analog GTPγS [PDB file 1TND], and the transition state between GTP-bound and GDP-bound state is represented by G{alpha}t bound to GDP-AlF4 [PDB file 1TAD], which is a transition state mimetic. The GDP-bound structure was morphed into each of the other structures by computer to provide an idea of how nucleotide binding and hydrolysis contribute to changes in structure during the G protein activation and inactivation cycle. The slow step in the overall cycle of activation and hydrolysis is the release of GDP.

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Format: Video file (.avi)

Size: 8.9 MB

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Citation: A. M. Preininger, H. E. Hamm, G protein signaling: Insights from new structures. Sci. STKE 2004, re3 (2004).

© 2004 American Association for the Advancement of Science

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