3u1a

From Proteopedia

(Difference between revisions)

Revision as of 16:49, 5 August 2016

N-terminal 81-aa fragment of smooth muscle tropomyosin alpha

Structural highlights

3u1a is a 4 chain structure with sequence from Chick. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Related:	3u1c, 3u59
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

[TPM1_CHICK] Binds to actin filaments in muscle and non-muscle cells. Plays a central role, in association with the troponin complex, in the calcium dependent regulation of vertebrate striated muscle contraction. Smooth muscle contraction is regulated by interaction with caldesmon. In non-muscle cells is implicated in stabilizing cytoskeleton actin filaments.

Publication Abstract from PubMed

A large number of tropomyosin (Tm) isoforms function as gatekeepers of the actin filament, controlling the spatiotemporal access of actin-binding proteins to specialized actin networks. Residues approximately 40-80 vary significantly among Tm isoforms, but the impact of sequence variation on Tm structure and interactions with actin is poorly understood, because structural studies have focused on skeletal muscle Tmalpha. We describe structures of N-terminal fragments of smooth muscle Tmalpha and Tmbeta (sm-Tmalpha and sm-Tmbeta). The 2.0-A structure of sm-Tmalpha81 (81-aa) resembles that of skeletal Tmalpha, displaying a similar super-helical twist matching the contours of the actin filament. The 1.8-A structure of sm-Tmalpha98 (98-aa) unexpectedly reveals an antiparallel coiled coil, with the two chains staggered by only 4 amino acids and displaying hydrophobic core interactions similar to those of the parallel dimer. In contrast, the 2.5-A structure of sm-Tmbeta98, containing Gly-Ala-Ser at the N terminus to mimic acetylation, reveals a parallel coiled coil. None of the structures contains coiled-coil stabilizing elements, favoring the formation of head-to-tail overlap complexes in four of five crystallographically independent parallel dimers. These complexes show similarly arranged 4-helix bundles stabilized by hydrophobic interactions, but the extent of the overlap varies between sm-Tmbeta98 and sm-Tmalpha81 from 2 to 3 helical turns. The formation of overlap complexes thus appears to be an intrinsic property of the Tm coiled coil, with the specific nature of hydrophobic contacts determining the extent of the overlap. Overall, the results suggest that sequence variation among Tm isoforms has a limited effect on actin binding but could determine its gatekeeper function.

Structural analysis of smooth muscle tropomyosin alpha and beta isoforms.,Rao JN, Rivera-Santiago R, Li XE, Lehman W, Dominguez R J Biol Chem. 2012 Jan 27;287(5):3165-74. Epub 2011 Nov 27. PMID:22119916^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Rao JN, Rivera-Santiago R, Li XE, Lehman W, Dominguez R. Structural analysis of smooth muscle tropomyosin alpha and beta isoforms. J Biol Chem. 2012 Jan 27;287(5):3165-74. Epub 2011 Nov 27. PMID:22119916 doi:10.1074/jbc.M111.307330

1 Structural highlights
2 Function
3 Publication Abstract from PubMed
4 See Also
5 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/3u1a"

@@ Line 1: / Line 1: @@
 ==N-terminal 81-aa fragment of smooth muscle tropomyosin alpha==
 <StructureSection load='3u1a' size='340' side='right' caption='[[3u1a]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
 == Structural highlights ==
-<table><tr><td colspan='2'>[[3u1a]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3U1A OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3U1A FirstGlance]. <br>
+<table><tr><td colspan='2'>[[3u1a]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/Chick Chick]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3U1A OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3U1A FirstGlance]. <br>
 </td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[3u1c|3u1c]], [[3u59|3u59]]</td></tr>
-<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3u1a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3u1a OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3u1a RCSB], [http://www.ebi.ac.uk/pdbsum/3u1a PDBsum]</span></td></tr>
+<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3u1a FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3u1a OCA], [http://pdbe.org/3u1a PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3u1a RCSB], [http://www.ebi.ac.uk/pdbsum/3u1a PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=3u1a ProSAT]</span></td></tr>
 </table>
 == Function ==
@@ Line 16: / Line 17: @@
 From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
 </div>
+<div class="pdbe-citations 3u1a" style="background-color:#fffaf0;"></div>
 ==See Also==
@@ Line 23: / Line 25: @@
 __TOC__
 </StructureSection>
-[[Category: Gallus gallus]]
+[[Category: Chick]]
 [[Category: Dominguez, R]]
 [[Category: Jampani, N]]

3u1a

From Proteopedia

Revision as of 16:49, 5 August 2016

N-terminal 81-aa fragment of smooth muscle tropomyosin alpha

Structural highlights

Function

Publication Abstract from PubMed

See Also

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

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