1nwk
From Proteopedia
(New page: 200px<br /><applet load="1nwk" size="450" color="white" frame="true" align="right" spinBox="true" caption="1nwk, resolution 1.85Å" /> '''CRYSTAL STRUCTURE OF...) |
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| - | [[Image:1nwk.gif|left|200px]]<br /><applet load="1nwk" size=" | + | [[Image:1nwk.gif|left|200px]]<br /><applet load="1nwk" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1nwk, resolution 1.85Å" /> | caption="1nwk, resolution 1.85Å" /> | ||
'''CRYSTAL STRUCTURE OF MONOMERIC ACTIN IN THE ATP STATE'''<br /> | '''CRYSTAL STRUCTURE OF MONOMERIC ACTIN IN THE ATP STATE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | A nucleotide-dependent conformational change regulates actin filament | + | A nucleotide-dependent conformational change regulates actin filament dynamics. Yet, the structural basis of this mechanism remains controversial. The x-ray crystal structure of tetramethylrhodamine-5-maleimide-actin with bound AMPPNP, a non-hydrolyzable ATP analog, was determined to 1.85-A resolution. A comparison of this structure to that of tetramethylrhodamine-5-maleimide-actin with bound ADP, determined previously under similar conditions, reveals how the release of the nucleotide gamma-phosphate sets in motion a sequence of events leading to a conformational change in subdomain 2. The side chain of Ser-14 in the catalytic site rotates upon Pi release, triggering the rearrangement of the loop containing the methylated His-73, referred to as the sensor loop. This in turn causes a transition in the DNase I-binding loop in subdomain 2 from a disordered loop in ATP-actin to an ordered alpha-helix in ADP-actin. Despite this conformational change, the nucleotide cleft remains closed in ADP-actin, similar to ATP-actin. An analysis of the existing structures of members of the actin superfamily suggests that the cleft is open in the nucleotide-free state. |
==About this Structure== | ==About this Structure== | ||
| - | 1NWK is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Oryctolagus_cuniculus Oryctolagus cuniculus] with CA, ANP and RHO as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1NWK is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Oryctolagus_cuniculus Oryctolagus cuniculus] with <scene name='pdbligand=CA:'>CA</scene>, <scene name='pdbligand=ANP:'>ANP</scene> and <scene name='pdbligand=RHO:'>RHO</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NWK OCA]. |
==Reference== | ==Reference== | ||
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[[Category: tetramethylrhodamine-5-maleimide]] | [[Category: tetramethylrhodamine-5-maleimide]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:10:51 2008'' |
Revision as of 12:10, 21 February 2008
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CRYSTAL STRUCTURE OF MONOMERIC ACTIN IN THE ATP STATE
Overview
A nucleotide-dependent conformational change regulates actin filament dynamics. Yet, the structural basis of this mechanism remains controversial. The x-ray crystal structure of tetramethylrhodamine-5-maleimide-actin with bound AMPPNP, a non-hydrolyzable ATP analog, was determined to 1.85-A resolution. A comparison of this structure to that of tetramethylrhodamine-5-maleimide-actin with bound ADP, determined previously under similar conditions, reveals how the release of the nucleotide gamma-phosphate sets in motion a sequence of events leading to a conformational change in subdomain 2. The side chain of Ser-14 in the catalytic site rotates upon Pi release, triggering the rearrangement of the loop containing the methylated His-73, referred to as the sensor loop. This in turn causes a transition in the DNase I-binding loop in subdomain 2 from a disordered loop in ATP-actin to an ordered alpha-helix in ADP-actin. Despite this conformational change, the nucleotide cleft remains closed in ADP-actin, similar to ATP-actin. An analysis of the existing structures of members of the actin superfamily suggests that the cleft is open in the nucleotide-free state.
About this Structure
1NWK is a Single protein structure of sequence from Oryctolagus cuniculus with , and as ligands. Full crystallographic information is available from OCA.
Reference
Crystal structure of monomeric actin in the ATP state. Structural basis of nucleotide-dependent actin dynamics., Graceffa P, Dominguez R, J Biol Chem. 2003 Sep 5;278(36):34172-80. Epub 2003 Jun 17. PMID:12813032
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