1cip

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(New page: 200px<br /><applet load="1cip" size="450" color="white" frame="true" align="right" spinBox="true" caption="1cip, resolution 1.5&Aring;" /> '''GI-ALPHA-1 SUBUNIT OF...)
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[[Image:1cip.gif|left|200px]]<br /><applet load="1cip" size="350" color="white" frame="true" align="right" spinBox="true"
caption="1cip, resolution 1.5&Aring;" />
caption="1cip, resolution 1.5&Aring;" />
'''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==
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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.
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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==
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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://ispc.weizmann.ac.il/oca-bin/ocashort?id=1CIP OCA].
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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]]
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''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 12:29:37 2007''
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''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


1cip, resolution 1.5Å

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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 and 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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