1tit
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(New page: 200px<br /><applet load="1tit" size="450" color="white" frame="true" align="right" spinBox="true" caption="1tit" /> '''TITIN, IG REPEAT 27, NMR, MINIMIZED AVERAGE ...)
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Revision as of 01:11, 21 November 2007
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TITIN, IG REPEAT 27, NMR, MINIMIZED AVERAGE STRUCTURE
Overview
BACKGROUND. The giant muscle protein titin forms a filament which spans, half of the sarcomere and performs, along its length, quite diverse, functions. The region of titin located in the sarcomere I-band is believed, to play a major role in extensibility and passive elasticity of muscle. In, the I-band, the titin sequence consists mostly of repetitive motifs of, tandem immunoglobulin-like (Ig) modules intercalated by a potentially, non-globular region. The highly repetitive titin architecture suggests, that the molecular basis of its mechanical properties be approached, through the characterization of the isolated components of the I-band and, their interfaces. In the present paper, we report on the structure, determination in solution of a representative Ig module from the I-band, (I27) as solved by NMR techniques. RESULTS. The structure of I27 consists, of a beta sandwich formed by two four-stranded sheets (named ABED and, A'GFC). This fold belongs to the intermediate frame (I frame) of the, immunoglobulin superfamily. Comparison of I27 with another titin module, from the region located in the M-line (M5) shows that two loops (between, the B and C and the F and G strands) are shorter in I27, conferring a less, elongated appearance to this structure. Such a feature is specific to the, Ig domains in the I-band and might therefore be related to the functions, of the protein in this region. The structure of tandem Ig domains as, modeled from I27 suggests the presence of hinge regions connecting, contiguous modules. CONCLUSIONS. We suggest that titin Ig domains in the, I-band function as extensible components of muscle elasticity by, stretching the hinge regions.
About this Structure
1TIT is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Immunoglobulin-like modules from titin I-band: extensible components of muscle elasticity., Improta S, Politou AS, Pastore A, Structure. 1996 Mar 15;4(3):323-37. PMID:8805538
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