1twb: Difference between revisions

Revision as of 16:18, 21 February 2008

SspB disulfide crosslinked to an ssrA degradation tag

OverviewOverview

The SspB adaptor enhances ClpXP degradation by binding the ssrA degradation tag of substrates and the AAA+ ClpX unfoldase. To probe the mechanism of substrate delivery, we engineered a disulfide bond between the ssrA tag and SspB and demonstrated otherwise normal interactions by solving the crystal structure. Although the covalent link prevents adaptor.substrate dissociation, ClpXP degraded GFP-ssrA that was disulfide bonded to the adaptor. Thus, crosslinked substrate must be handed directly from SspB to ClpX. The ssrA tag in the covalent adaptor complex interacted with ClpX.ATPgammaS but not ClpX.ADP, suggesting that handoff occurs in the ATP bound enzyme. By contrast, SspB alone bound ClpX in both nucleotide states. Similar handoff mechanisms will undoubtedly be used by many AAA+ adaptors and enzymes, allowing assembly of delivery complexes in either nucleotide state, engagement of the recognition tag in the ATP state, and application of an unfolding force to the attached protein following hydrolysis.

About this StructureAbout this Structure

1TWB is a Single protein structure of sequence from Haemophilus influenzae. Full crystallographic information is available from OCA.

ReferenceReference

Nucleotide-dependent substrate handoff from the SspB adaptor to the AAA+ ClpXP protease., Bolon DN, Grant RA, Baker TA, Sauer RT, Mol Cell. 2004 Nov 5;16(3):343-50. PMID:15525508

Page seeded by OCA on Thu Feb 21 15:18:03 2008

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OCA

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-[[Image:1twb.gif|left|200px]]<br /><applet load="1twb" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1twb.gif|left|200px]]<br /><applet load="1twb" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1twb, resolution 1.90&Aring;" />
 '''SspB disulfide crosslinked to an ssrA degradation tag'''<br />
 ==Overview==
-The SspB adaptor enhances ClpXP degradation by binding the ssrA, degradation tag of substrates and the AAA+ ClpX unfoldase. To probe the, mechanism of substrate delivery, we engineered a disulfide bond between, the ssrA tag and SspB and demonstrated otherwise normal interactions by, solving the crystal structure. Although the covalent link prevents, adaptor.substrate dissociation, ClpXP degraded GFP-ssrA that was disulfide, bonded to the adaptor. Thus, crosslinked substrate must be handed directly, from SspB to ClpX. The ssrA tag in the covalent adaptor complex interacted, with ClpX.ATPgammaS but not ClpX.ADP, suggesting that handoff occurs in, the ATP bound enzyme. By contrast, SspB alone bound ClpX in both, nucleotide states. Similar handoff mechanisms will undoubtedly be used by, many AAA+ adaptors and enzymes, allowing assembly of delivery complexes in, either nucleotide state, engagement of the recognition tag in the ATP, state, and application of an unfolding force to the attached protein, following hydrolysis.
+The SspB adaptor enhances ClpXP degradation by binding the ssrA degradation tag of substrates and the AAA+ ClpX unfoldase. To probe the mechanism of substrate delivery, we engineered a disulfide bond between the ssrA tag and SspB and demonstrated otherwise normal interactions by solving the crystal structure. Although the covalent link prevents adaptor.substrate dissociation, ClpXP degraded GFP-ssrA that was disulfide bonded to the adaptor. Thus, crosslinked substrate must be handed directly from SspB to ClpX. The ssrA tag in the covalent adaptor complex interacted with ClpX.ATPgammaS but not ClpX.ADP, suggesting that handoff occurs in the ATP bound enzyme. By contrast, SspB alone bound ClpX in both nucleotide states. Similar handoff mechanisms will undoubtedly be used by many AAA+ adaptors and enzymes, allowing assembly of delivery complexes in either nucleotide state, engagement of the recognition tag in the ATP state, and application of an unfolding force to the attached protein following hydrolysis.
 ==About this Structure==
-TWB is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Haemophilus_influenzae Haemophilus influenzae]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1TWB OCA].
+TWB is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Haemophilus_influenzae Haemophilus influenzae]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1TWB OCA].
 ==Reference==
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 [[Category: Haemophilus influenzae]]
 [[Category: Single protein]]
-[[Category: Baker, T.A.]]
+[[Category: Baker, T A.]]
-[[Category: Bolon, D.N.]]
+[[Category: Bolon, D N.]]
-[[Category: Grant, R.A.]]
+[[Category: Grant, R A.]]
-[[Category: Sauer, R.T.]]
+[[Category: Sauer, R T.]]
 [[Category: aaa+]]
 [[Category: adaptor]]
@@ Line 22: / Line 22: @@
 [[Category: specificity factor]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 03:38:34 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:18:03 2008''