1svs: Difference between revisions
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[[Image:1svs.jpg|left|200px]]< | [[Image:1svs.jpg|left|200px]] | ||
'''Structure of the K180P mutant of Gi alpha subunit bound to GppNHp.''' | {{Structure | ||
|PDB= 1svs |SIZE=350|CAPTION= <scene name='initialview01'>1svs</scene>, resolution 1.5Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene> and <scene name='pdbligand=GNP:PHOSPHOAMINOPHOSPHONIC ACID-GUANYLATE ESTER'>GNP</scene> | |||
|ACTIVITY= [http://en.wikipedia.org/wiki/Heterotrimeric_G-protein_GTPase Heterotrimeric G-protein GTPase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.6.5.1 3.6.5.1] | |||
|GENE= GNAI1, GNAI-1 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=10116 Rattus norvegicus]) | |||
}} | |||
'''Structure of the K180P mutant of Gi alpha subunit bound to GppNHp.''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1SVS is a [ | 1SVS is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SVS OCA]. | ||
==Reference== | ==Reference== | ||
Uncoupling conformational change from GTP hydrolysis in a heterotrimeric G protein alpha-subunit., Thomas CJ, Du X, Li P, Wang Y, Ross EM, Sprang SR, Proc Natl Acad Sci U S A. 2004 May 18;101(20):7560-5. Epub 2004 May 5. PMID:[http:// | Uncoupling conformational change from GTP hydrolysis in a heterotrimeric G protein alpha-subunit., Thomas CJ, Du X, Li P, Wang Y, Ross EM, Sprang SR, Proc Natl Acad Sci U S A. 2004 May 18;101(20):7560-5. Epub 2004 May 5. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/15128951 15128951] | ||
[[Category: Heterotrimeric G-protein GTPase]] | [[Category: Heterotrimeric G-protein GTPase]] | ||
[[Category: Rattus norvegicus]] | [[Category: Rattus norvegicus]] | ||
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[[Category: k180p mutation]] | [[Category: k180p mutation]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 14:10:17 2008'' | ||
Revision as of 12:10, 20 March 2008
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| 1svs, resolution 1.5Å | |||||||||||||
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| Ligands: | MG and GNP | ||||||||||||
| Gene: | GNAI1, GNAI-1 (Rattus norvegicus) | ||||||||||||
| Activity: | Heterotrimeric G-protein GTPase, with EC number 3.6.5.1 | ||||||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||||||
Structure of the K180P mutant of Gi alpha subunit bound to GppNHp.
Overview
Heterotrimeric G protein alpha (G alpha) subunits possess intrinsic GTPase activity that leads to functional deactivation with a rate constant of approximately 2 min(-1) at 30 degrees C. GTP hydrolysis causes conformational changes in three regions of G alpha, including Switch I and Switch II. Mutation of G202-->A in Switch II of G alpha(i1) accelerates the rates of both GTP hydrolysis and conformational change, which is measured by the loss of fluorescence from Trp-211 in Switch II. Mutation of K180-->P in Switch I increases the rate of conformational change but decreases the GTPase rate, which causes transient but substantial accumulation of a low-fluorescence G alpha(i1).GTP species. Isothermal titration calorimetric analysis of the binding of (G202A)G alpha(i1) and (K180P)G alpha(i1) to the GTPase-activating protein RGS4 indicates that the G202A mutation stabilizes the pretransition state-like conformation of G alpha(i1) that is mimicked by the complex of G alpha(i1) with GDP and magnesium fluoroaluminate, whereas the K180P mutation destabilizes this state. The crystal structures of (K180P)G alpha(i1) bound to a slowly hydrolyzable GTP analog, and the GDP.magnesium fluoroaluminate complex provide evidence that the Mg(2+) binding site is destabilized and that Switch I is torsionally restrained by the K180P mutation. The data are consistent with a catalytic mechanism for G alpha in which major conformational transitions in Switch I and Switch II are obligate events that precede the bond-breaking step in GTP hydrolysis. In (K180P)G alpha(i1), the two events are decoupled kinetically, whereas in the native protein they are concerted.
About this Structure
1SVS is a Single protein structure of sequence from Rattus norvegicus. Full crystallographic information is available from OCA.
Reference
Uncoupling conformational change from GTP hydrolysis in a heterotrimeric G protein alpha-subunit., Thomas CJ, Du X, Li P, Wang Y, Ross EM, Sprang SR, Proc Natl Acad Sci U S A. 2004 May 18;101(20):7560-5. Epub 2004 May 5. PMID:15128951
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