1b0w
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(New page: 200px<br /><applet load="1b0w" size="450" color="white" frame="true" align="right" spinBox="true" caption="1b0w, resolution 1.80Å" /> '''Structural compariso...)
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Revision as of 09:08, 20 November 2007
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Structural comparison of amyloidogenic light chain dimer in two crystal forms with nonamyloidogenic counterparts
Overview
The most common form of hereditary systemic amyloidosis is familial, amyloidotic polyneuropathy associated with single amino acid changes in, the plasma protein transthyretin. So far, high resolution structures of, only three amyloidogenic variants (Met30, Ser84, Ile122) and one, non-amyloidogenic variant (Thr109) have been reported complemented by, X-ray fiber diffraction studies and image reconstruction from electron, micrographs of amyloid fibrils. To investigate the role of structural, factors in this disease, we extended our studies to other transthyretin, variants. We report crystallization and structural investigations of three, amyloidogenic (Arg10, Ala60, Tyr77) and two non-amyloidogenic variants, (Ser6, Met119). The similarity of these structures to normal transthyretin, does not give direct clues to the fibril forming process. Since, transthyretin amyloid fibrils contain a major fragment starting at, position 49, besides the intact molecule, we calculated the solvent, accessibility of residue 48. Indeed, all amyloidogenic variants show an, increased main chain solvent exposure when compared to normal, transthyretin and non-amyloidogenic variants, which can be postulated to, result in increased susceptibility to proteolysis. After limited, proteolysis, dimers are incapable of reassociation to native tetramers. We, present a model for amyloid fibril formation based on formation of fibrils, from N-terminal truncated dimers as building blocks.
About this Structure
1B0W is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Tertiary structures of amyloidogenic and non-amyloidogenic transthyretin variants: new model for amyloid fibril formation., Schormann N, Murrell JR, Benson MD, Amyloid. 1998 Sep;5(3):175-87. PMID:9818054
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