2g4e
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Crystal structure of transthyretin mutant I84A at neutral pH
OverviewOverview
Several proteins, including transthyretin (TTR), can generate in tissues, extracellular insoluble aggregates, in the form of fibrils, that are, associated with pathological states known as amyloidoses. To date, more, than 80 different TTR point mutations have been associated with hereditary, amyloidosis in humans. In vitro, the formation of amyloid fibrils by human, TTR is known to be triggered by acidic pH. We show here that, in vitro, the natural amyloidogenic I84S and the non-natural I84A TTR mutant forms, exhibit a propensity to produce fibrils in an acidic medium significantly, higher than that of wild-type TTR. The two mutant forms have been, crystallized at both neutral and acidic pH. Their neutral pH crystal, structures are very similar to that of wild-type TTR, consistent with, previous evidence indicating that only minor structural changes are, induced by amyloidogenic mutations. On the contrary, their crystal, structures at moderately low pH (4.6) show significant conformational, differences as compared to their neutral pH structures. Remarkably, such, changes are not induced in wild-type TTR crystallized at low pH. The most, relevant consist of the unwinding of the TTR short alpha-helix and of the, change in conformation of the loop connecting the alpha-helix to, beta-strand F. Only one monomer of the crystallographic dimer is affected, causing a disruption of the tetrameric symmetry. This asymmetry and a, possible destabilization of the tetrameric quaternary structure of TTR may, be responsible for the amyloidogenic potential of the two TTR mutant forms, at low pH.
DiseaseDisease
Known diseases associated with this structure: Amyloid neuropathy, familial, several allelic types OMIM:[176300], Amyloidosis, senile systemic OMIM:[176300], Carpal tunnel syndrome, familial OMIM:[176300], Dystransthyretinemic hyperthyroxinemia OMIM:[176300]
About this StructureAbout this Structure
2G4E is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Acidic pH-induced Conformational Changes in Amyloidogenic Mutant Transthyretin., Pasquato N, Berni R, Folli C, Alfieri B, Cendron L, Zanotti G, J Mol Biol. 2007 Feb 23;366(3):711-9. Epub 2006 Dec 1. PMID:17196219
Page seeded by OCA on Mon Nov 12 22:14:44 2007