1ic2
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(New page: 200px<br /><applet load="1ic2" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ic2, resolution 2.0Å" /> '''DECIPHERING THE DESIG...)
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Revision as of 15:09, 20 November 2007
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DECIPHERING THE DESIGN OF THE TROPOMYOSIN MOLECULE
Overview
The crystal structure at 2.0-A resolution of an 81-residue N-terminal, fragment of muscle alpha-tropomyosin reveals a parallel two-stranded, alpha-helical coiled-coil structure with a remarkable core. The high, alanine content of the molecule is clustered into short regions where the, local 2-fold symmetry is broken by a small (approximately 1.2-A) axial, staggering of the helices. The joining of these regions with neighboring, segments, where the helices are in axial register, gives rise to specific, bends in the molecular axis. We observe such bends to be widely, distributed in two-stranded alpha-helical coiled-coil proteins. This, asymmetric design in a dimer of identical (or highly similar) sequences, allows the tropomyosin molecule to adopt multiple bent conformations. The, seven alanine clusters in the core of the complete molecule (which spans, seven monomers of the actin helix) promote the semiflexible winding of the, tropomyosin filament necessary for its regulatory role in muscle, contraction.
About this Structure
1IC2 is a Single protein structure of sequence from Gallus gallus. Full crystallographic information is available from OCA.
Reference
Deciphering the design of the tropomyosin molecule., Brown JH, Kim KH, Jun G, Greenfield NJ, Dominguez R, Volkmann N, Hitchcock-DeGregori SE, Cohen C, Proc Natl Acad Sci U S A. 2001 Jul 17;98(15):8496-501. Epub 2001 Jul 3. PMID:11438684
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