1cip: Difference between revisions
New page: left|200px<br /><applet load="1cip" size="450" color="white" frame="true" align="right" spinBox="true" caption="1cip, resolution 1.5Å" /> '''GI-ALPHA-1 SUBUNIT OF... |
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[[Image:1cip.gif|left|200px]]<br /><applet load="1cip" size=" | [[Image:1cip.gif|left|200px]]<br /><applet load="1cip" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1cip, resolution 1.5Å" /> | caption="1cip, resolution 1.5Å" /> | ||
'''GI-ALPHA-1 SUBUNIT OF GUANINE NUCLEOTIDE-BINDING PROTEIN COMPLEXED WITH A GTP ANALOGUE'''<br /> | '''GI-ALPHA-1 SUBUNIT OF GUANINE NUCLEOTIDE-BINDING PROTEIN COMPLEXED WITH A GTP ANALOGUE'''<br /> | ||
==Overview== | ==Overview== | ||
The structure of the G protein Gialpha1 complexed with the nonhydrolyzable | The structure of the G protein Gialpha1 complexed with the nonhydrolyzable GTP analog guanosine-5'-(betagamma-imino)triphosphate (GppNHp) has been determined at a resolution of 1.5 A. In the active site of Gialpha1. GppNHp, a water molecule is hydrogen bonded to the side chain of Glu43 and to an oxygen atom of the gamma-phosphate group. The side chain of the essential catalytic residue Gln204 assumes a conformation which is distinctly different from that observed in complexes with either guanosine 5'-O-3-thiotriphosphate or the transition state analog GDP.AlF4-. Hydrogen bonding and steric interactions position Gln204 such that it interacts with a presumptive nucleophilic water molecule, but cannot interact with the pentacoordinate transition state. Gln204 must be released from this auto-inhibited state to participate in catalysis. RGS proteins may accelerate the rate of GTP hydrolysis by G protein alpha subunits, in part, by inserting an amino acid side chain into the site occupied by Gln204, thereby destabilizing the auto-inhibited state of Galpha. | ||
==About this Structure== | ==About this Structure== | ||
1CIP is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] with MG and GNP as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | 1CIP is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] with <scene name='pdbligand=MG:'>MG</scene> and <scene name='pdbligand=GNP:'>GNP</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CIP OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: gtpase]] | [[Category: gtpase]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:06:26 2008'' | ||
Revision as of 10:06, 21 February 2008
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GI-ALPHA-1 SUBUNIT OF GUANINE NUCLEOTIDE-BINDING PROTEIN COMPLEXED WITH A GTP ANALOGUE
Overview
The structure of the G protein Gialpha1 complexed with the nonhydrolyzable GTP analog guanosine-5'-(betagamma-imino)triphosphate (GppNHp) has been determined at a resolution of 1.5 A. In the active site of Gialpha1. GppNHp, a water molecule is hydrogen bonded to the side chain of Glu43 and to an oxygen atom of the gamma-phosphate group. The side chain of the essential catalytic residue Gln204 assumes a conformation which is distinctly different from that observed in complexes with either guanosine 5'-O-3-thiotriphosphate or the transition state analog GDP.AlF4-. Hydrogen bonding and steric interactions position Gln204 such that it interacts with a presumptive nucleophilic water molecule, but cannot interact with the pentacoordinate transition state. Gln204 must be released from this auto-inhibited state to participate in catalysis. RGS proteins may accelerate the rate of GTP hydrolysis by G protein alpha subunits, in part, by inserting an amino acid side chain into the site occupied by Gln204, thereby destabilizing the auto-inhibited state of Galpha.
About this Structure
1CIP is a Single protein structure of sequence from Rattus norvegicus with MG and GNP as ligands. Full crystallographic information is available from OCA.
Reference
Structure of Gialpha1.GppNHp, autoinhibition in a galpha protein-substrate complex., Coleman DE, Sprang SR, J Biol Chem. 1999 Jun 11;274(24):16669-72. PMID:10358003
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