14 rezultatet
Cylindrin is a six-stranded antiparallel beta barrel obtained from amyloidogenic strands of crystallin. It induces cell toxicity through an unknown mechanism. In this work, the potential use of the structure of cylindrin as a template for modeling amyloid pores-hypothetical transmembrane structures
We introduce Replica-Exchange-with-Tunneling (RET) simulations as a tool for studies of the conversion between polymorphic amyloids. For the 11-residue amyloid-forming cylindrin peptide we show that this technique allows for a more efficient sampling of the formation and interconversion between
Small-soluble amyloid oligomers are believed to play a significant role in the pathology of amyloid diseases. Recently, the atomic structure of a toxic oligomer formed by an 11 residue and its tandem repeat was found to have an out-off register antiparallel β-strands in the shape of a β-barrel. In
In order to evaluate potential therapeutic targets for treatment of amyloidoses such as Alzheimer's disease (AD), it is essential to determine the structures of toxic amyloid oligomers. However, for the amyloid β-protein peptide (Aβ), thought to be the seminal neuropathogenetic agent in AD, its fast
Examples of homomeric β-helices and β-barrels have recently emerged. Here we generalize the theory for the shear number in β-barrels to encompass β-helices and homomeric structures. We introduce the concept of the "β-strip," the set of parallel or antiparallel neighboring strands, from which the
Although aberrant protein aggregation has been conclusively linked to dozens of devastating amyloid diseases, scientists remain puzzled about the molecular features that render amyloid fibrils or small oligomers toxic. Here, we report a previously unobserved type of amyloid fibril that tests as
A predictive coarse-grained protein force field [associative memory, water-mediated, structure, and energy model for molecular dynamics (AWSEM)-MD] is used to study the energy landscapes and relative stabilities of amyloid-β protein (1-40) in the monomer and all of its oligomeric forms up to an
IAPP, a 37 amino-acid peptide hormone belonging to the calcitonin family, is an intrinsically disordered protein that is coexpressed and cosecreted along with insulin by pancreatic islet β-cells in response to meals. IAPP plays a physiological role in glucose regulation; however, in certain species,
Amyloid diseases, including Alzheimer's, Parkinson's, and the prion conditions, are each associated with a particular protein in fibrillar form. These amyloid fibrils were long suspected to be the disease agents, but evidence suggests that smaller, often transient and polymorphic oligomers are the
Dβ (or D-iso)- and Lβ- (or iso)- aspartyl (Asp) residues are accumulated in aged lens crystallins and amyloid beta (Aβ) proteins, respectively, as a result of spontaneous, nonenzymatic isomerization of normal Lα-Asp. To explore why such uncommon Asp isomers are accumulated, the stability of Lα-,
Many protein and peptide sequences are self-assembled into β-sheet-rich fibrous structures called amyloids. Their atomic details provide insights into fundamental knowledge related to amyloid diseases. To study the detailed structure of the amyloid, we have developed a model system that mimics the
We propose a variant of the recently found S-shaped Aβ1-42-motif that is characterized by out-of-register C-terminal β-strands. We show that chains with this structure can form not only fibrils that are compatible with the NMR signals but also barrel-shaped oligomers that resemble the ones formed by
Amyloidogenic proteins generally form intermolecularly hydrogen-bonded β-sheet aggregates, including parallel, in-register β-sheets (recognized by antiserum OC) or antiparallel β-sheets, β-solenoids, β-barrels, and β-cylindrins (recognized by antiserum A11). Although these groups share many common
The islet in type 2 diabetes (T2DM) is characterized by a deficit in β-cells, increased β-cell apoptosis, and extracellular amyloid deposits derived from islet amyloid polypeptide (IAPP). In the absence of longitudinal studies, it is unknown if the low β-cell mass in T2DM precedes diabetes onset (is