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1.
Papanikolopoulou K Schoehn G Forge V Forsyth VT Riekel C Hernandez JF Ruigrok RW Mitraki A 《The Journal of biological chemistry》2005,280(4):2481-2490
Amyloid fibrils are fibrous beta-structures that derive from abnormal folding and assembly of peptides and proteins. Despite a wealth of structural studies on amyloids, the nature of the amyloid structure remains elusive; possible connections to natural, beta-structured fibrous motifs have been suggested. In this work we focus on understanding amyloid structure and formation from sequences of a natural, beta-structured fibrous protein. We show that short peptides (25 to 6 amino acids) corresponding to repetitive sequences from the adenovirus fiber shaft have an intrinsic capacity to form amyloid fibrils as judged by electron microscopy, Congo Red binding, infrared spectroscopy, and x-ray fiber diffraction. In the presence of the globular C-terminal domain of the protein that acts as a trimerization motif, the shaft sequences adopt a triple-stranded, beta-fibrous motif. We discuss the possible structure and arrangement of these sequences within the amyloid fibril, as compared with the one adopted within the native structure. A 6-amino acid peptide, corresponding to the last beta-strand of the shaft, was found to be sufficient to form amyloid fibrils. Structural analysis of these amyloid fibrils suggests that perpendicular stacking of beta-strand repeat units is an underlying common feature of amyloid formation. 相似文献
2.
Papanikolopoulou K Teixeira S Belrhali H Forsyth VT Mitraki A van Raaij MJ 《Journal of molecular biology》2004,342(1):219-227
Adenovirus fibres are trimeric proteins that consist of a globular C-terminal domain, a central fibrous shaft and an N-terminal part that attaches to the viral capsid. In the presence of the globular C-terminal domain, which is necessary for correct trimerisation, the shaft segment adopts a triple beta-spiral conformation. We have replaced the head of the fibre by the trimerisation domain of the bacteriophage T4 fibritin, the foldon. Two different fusion constructs were made and crystallised, one with an eight amino acid residue linker and one with a linker of only two residues. X-ray crystallographic studies of both fusion proteins shows that residues 319-391 of the adenovirus type 2 fibre shaft fold into a triple beta-spiral fold indistinguishable from the native structure, although this is now resolved at a higher resolution of 1.9 A. The foldon residues 458-483 also adopt their natural structure. The intervening linkers are not well ordered in the crystal structures. This work shows that the shaft sequences retain their capacity to fold into their native beta-spiral fibrous fold when fused to a foreign C-terminal trimerisation motif. It provides a structural basis to artificially trimerise longer adenovirus shaft segments and segments from other trimeric beta-structured fibre proteins. Such artificial fibrous constructs, amenable to crystallisation and solution studies, can offer tractable model systems for the study of beta-fibrous structure. They can also prove useful for gene therapy and fibre engineering applications. 相似文献
3.
Pathogenesis, diagnosis and treatment of systemic amyloidosis 总被引:9,自引:0,他引:9
Pepys MB 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2001,356(1406):203-211
Amyloidosis is a disorder of protein folding in which normally soluble proteins are deposited as abnormal, insoluble fibrils that disrupt tissue structure and cause disease. Although about 20 different unrelated proteins can form amyloid fibrils in vivo, all such fibrils share a common cross-beta core structure. Some natural wild-type proteins are inherently amyloidogenic, form fibrils and cause amyloidosis in old age or if present for long periods at abnormally high concentration. Other amyloidogenic proteins are acquired or inherited variants, containing amino-acid substitutions that render them unstable so that they populate partly unfolded states under physiological conditions, and these intermediates then aggregate in the stable amyloid fold. In addition to the fibrils, amyloid deposits always contain the non-fibrillar pentraxin plasma protein, serum amyloid P component (SAP), because it undergoes specific calcium-dependent binding to amyloid fibrils. SAP contributes to amyloidogenesis, probably by stabilizing amyloid fibrils and retarding their clearance. Radiolabelled SAP is an extremely useful, safe, specific, non-invasive, quantitative tracer for scintigraphic imaging of systemic amyloid deposits. Its use has demonstrated that elimination of the supply of amyloid fibril precursor proteins leads to regression of amyloid deposits with clinical benefit. Current treatment of amyloidosis comprises careful maintenance of impaired organ function, replacement of end-stage organ failure by dialysis or transplantation, and vigorous efforts to control underlying conditions responsible for production of fibril precursors. New approaches under development include drugs for stabilization of the native fold of precursor proteins, inhibition of fibrillogenesis, reversion of the amyloid to the native fold, and dissociation of SAP to accelerate amyloid fibril clearance in vivo. 相似文献
4.
Debasish Haldar Arindam Banerjee 《International journal of peptide research and therapeutics》2006,12(4):341-348
l-Ala modified analogues of amyloid β-peptide residue 17-20 LVFF (-l-Leu-l-Val-l-Phe-l-Phe-) have been designed and synthesized to study their self-assembling propensity, the nature of intermolecular interactions and rationalize with short hydrophobic sequences in the middle of Aβ that have important role in the neuropathology of Alzheimer’s disease. The peptides sequences LVFA and LAFA have been adopted from the β-sheet region of non-amyloidogenic proteins (hemoglobin-like falvoprotein and ATP synthase C chain, respectively). All the reported peptides self-associate into amyloid-like fibrils which are readily stained with a physiological dye Congo red and exhibits green gold birefringence under polarized light. The solid state FTIR studies of the fibrils reveal that the reported peptides self-associate through intermolecular hydrogen bonds to form antiparallel β-sheet structure, which is also supported by molecular modeling studies. This result suggests that l-Ala analogous of Aβ17-20, LVFA and LAFA also have virtually identical aggregation behavior. 相似文献
5.
Gjertrud Maurstad Marcus Prass Louise C. Serpell Pawel Sikorski 《European biophysics journal : EBJ》2009,38(8):1135-1140
Atomic force microscopy was used to investigate the stability of dehydrated amyloid fibrils formed by human islet polypeptide
(IAPP) and Aβ(1–42) peptides. IAPP amyloid fibrils were imaged in liquid (hydrated state) and in air (dehydrated). In addition,
fibrils dried on the mica surface were rehydrated and re-examined both in liquid and in air (after consecutive redrying).
As reported previously, the initial drying process does not result in any major change in the amyloid appearance and the dimensions
of the fibrils are preserved. However, when once-dried samples are rehydrated, fibril stability is lost. The fibrils disintegrate
into small particles that are attached to the mica surface. This process is further confirmed by studies of the rehydrated
samples after drying, on which the morphology of the fibrils is clearly changed. Similar behavior is observed for Aβ(1–42)
amyloid fibrils, which are apparently stable on first drying, but disintegrate on rehydration. The observed change indicates
that dehydration is causing a change in the internal structure of the amyloid fibrils. This has important implications for
studies of amyloid fibrils by other techniques. Due to the potential influence of hydration and sample history on amyloid
structure, preparation and study of amyloid samples with controlled humidity requires more consideration. 相似文献
6.
P. Patrizia Mangione Gennaro Esposito Annalisa Relini Sara Raimondi Riccardo Porcari Sofia Giorgetti Alessandra Corazza Federico Fogolari Amanda Penco Yuji Goto Young-Ho Lee Hisashi Yagi Ciro Cecconi Mohsin M. Naqvi Julian D. Gillmore Philip N. Hawkins Fabrizio Chiti Ranieri Rolandi Graham W. Taylor Mark B. Pepys Monica Stoppini Vittorio Bellotti 《The Journal of biological chemistry》2013,288(43):30917-30930
Systemic amyloidosis is a fatal disease caused by misfolding of native globular proteins, which then aggregate extracellularly as insoluble fibrils, damaging the structure and function of affected organs. The formation of amyloid fibrils in vivo is poorly understood. We recently identified the first naturally occurring structural variant, D76N, of human β2-microglobulin (β2m), the ubiquitous light chain of class I major histocompatibility antigens, as the amyloid fibril protein in a family with a new phenotype of late onset fatal hereditary systemic amyloidosis. Here we show that, uniquely, D76N β2m readily forms amyloid fibrils in vitro under physiological extracellular conditions. The globular native fold transition to the fibrillar state is primed by exposure to a hydrophobic-hydrophilic interface under physiological intensity shear flow. Wild type β2m is recruited by the variant into amyloid fibrils in vitro but is absent from amyloid deposited in vivo. This may be because, as we show here, such recruitment is inhibited by chaperone activity. Our results suggest general mechanistic principles of in vivo amyloid fibrillogenesis by globular proteins, a previously obscure process. Elucidation of this crucial causative event in clinical amyloidosis should also help to explain the hitherto mysterious timing and location of amyloid deposition. 相似文献
7.
The amyloid-like fibril is considered to be a macromolecular self-assemblage with a highly-ordered quaternary structure, in which numerous beta-stranded polypeptide chains align regularly. Therefore, this kind of fibril has the potential to be engineered into proteinaceous materials, although conformational alteration of proteins from their native form to the amyloid form is a misfolding and undesirable process related to amyloid diseases. In this study, we have attempted to design an artificial system to explore applicability of using the amyloid-like fibril as a construct possessing self-recognition and self-catalytic abilities. A peptide self-replicating system based on the beta-structure of the amyloid-like fibril was designed and constructed. The beta-stranded peptide was self-replicated by the native chemical ligation reaction, and the newly generated peptide was self-assembled into amyloid-like fibrils. Thus, the constructed system was of both chemical and conformational self-replicating fibrils. 相似文献
8.
Papanikolopoulou K Forge V Goeltz P Mitraki A 《The Journal of biological chemistry》2004,279(10):8991-8998
The folding of beta-structured, fibrous proteins is a largely unexplored area. A class of such proteins is used by viruses as adhesins, and recent studies revealed novel beta-structured motifs for them. We have been studying the folding and assembly of adenovirus fibers that consist of a globular C-terminal domain, a central fibrous shaft, and an N-terminal part that attaches to the viral capsid. The globular C-terminal, or "head" domain, has been postulated to be necessary for the trimerization of the fiber and might act as a registration signal that directs its correct folding and assembly. In this work, we replaced the head of the fiber by the trimerization domain of the bacteriophage T4 fibritin, termed "foldon." Two chimeric proteins, comprising the foldon domain connected at the C-terminal end of four fiber shaft repeats with or without the use of a natural linker sequence, fold into highly stable, SDS-resistant trimers. The structural signatures of the chimeric proteins as seen by CD and infrared spectroscopy are reported. The results suggest that the foldon domain can successfully replace the fiber head domain in ensuring correct trimerization of the shaft sequences. Biological implications and implications for engineering highly stable, beta-structured nanorods are discussed. 相似文献
9.
Céline Rivière Jean-Claude Delaunay Françoise Immel Christophe Cullin Jean-Pierre Monti 《Neurochemical research》2009,34(6):1120-1128
Alzheimer’s disease (AD) is characterized by deposits of amyloid in various tissues. The neuronal cytotoxicity of Aβ peptides
is attributed not only to various mechanisms but also to amyloid fibrils and soluble oligomeric intermediates. Consequently,
finding molecules to prevent or reverse the oligomerization and fibrillization of Aβ could be of therapeutic value in the
treatment of AD. We show that piceid, a polyphenol of the stilbene family, destabilized fibrils and oligomers to give back
monomers that are not neurotoxic molecules. The mechanism of this destabilization could be a dynamic interaction between the
polyphenol and the Aβ that could open the hydrophobic zipper and shift the reversible equilibrium “random coil⇔β-sheet” to
the disordered structure. 相似文献
10.
Protein deposition as amyloid fibrils underlies more than twenty severely debilitating human disorders. Interestingly, recent studies suggest that all peptides and proteins possess an intrinsic ability to assemble into amyloid fibrils similar to those observed in disease states. The common properties and characteristics of amyloid aggregates thus offer the prospect that simple model systems can be used to systematically assess the factors that predispose a native protein to form amyloid fibrils and understand the origin and progression of fatal disorders associated with amyloid formation. Here, we report the de novo design of a 17-residue peptide model system, referred to as cc, which forms a protein-like coiled-coil structure under ambient solution conditions but can be easily converted into amyloid fibrils by raising the temperature. Oxidation of methionine residues at selected hydrophobic positions completely abolished amyloid fibril formation of the peptide while not interfering with its coiled-coil structure. This finding indicates that a small number of site-specific hydrophobic interactions can play a major role in the packing of polypeptide chain segments within amyloid fibrils. The simplicity and characteristics of the cc system make it highly suitable for probing molecular details of the assembly of amyloid structures. Abbreviations used for amino acids follow the recommendations of the IUPAC-IUB Commission of Biochemical Nomenclature [Eur. J. Biochem., 138 (1984) 9]. 相似文献
11.
A. V. Maltsev O. V. Galzitskaya 《Biochemistry (Moscow) Supplemental Series B: Biomedical Chemistry》2010,4(3):228-236
Studies of neurodegenerative disorders attract much attention of the world scientific community due to increasing dissemination
of Alzheimer’s disease. The reason for such pathologies consists in transition of a “healthy” molecule or peptide from its
native conformation into a very stable “pathological” form. During this process, molecules existing in the “pathological”
conformation aggregate and form amyloid fibrils that can undergo an uncontrolled increase. Novel knowledge is required on
sporadic forms of Alzheimer’s disease, on the nature of triggering mechanisms of the conformational transitions of beta-amyloid
fragments from normally functioning proteins into new structure, nano-beta-amyloids, that escape of neuronal and whole-body
control resulted in the loss of neurons. This review summarized results of studies on the formation of amyloid fibrils and
their role in pathogenesis of amyloid diseases. 相似文献
12.
It has been suggested that, while the globular native forms of proteins are a side-chain-dominated compact structure evolved by pursuing a unique fold with optimal packing of amino acid residues, amyloid fibrils are a main-chain-dominated structure with an extensive hydrogen bond network. To address this issue, the effects of hydrostatic pressure on amyloid fibrils of beta2-microglobulin (beta2-m), involved in dialysis-related amyloidosis, were studied. A systematic analysis at various pressures and concentrations of guanidine hydrochloride conducted by monitoring thioflavin T fluorescence, light-scattering, and tryptophan fluorescence revealed contrasting conformational changes occurring consecutively: first, a pressure-induced reorganization of fibrils and then a pressure-induced unfolding. The changes in volume as well as the observed structural changes indicate that the beta2-m amyloid fibrils under ambient pressure are less tightly packed with a larger number of cavities, consistent with the main-chain-dominated amyloid structure. Moreover, the amyloid structure without optimal packing will enable various isoforms to form, suggesting the structural basis of multiple forms of amyloid fibrils in contrast to the unique native-fold. 相似文献
13.
Vieira MN Figueroa-Villar JD Meirelles MN Ferreira ST De Felice FG 《Cell biochemistry and biophysics》2006,44(3):549-553
Protein amyloid aggregation is associated with a number of important human pathologies, but the precise mechanisms underlying
the toxicity of amyloid aggregates are still incompletely understood. In this context, drugs capable of blocking or interfering
with the aggregation of amyloidogenic proteins should be considered in strategies aimed at the development of novel therapeutic
agents. Human lysozyme variants have been shown to form massive amyloid deposits in the livers and kidneys of individuals
affected by hereditary systemic amyloidosis. Currently, there are no clinical treatments available to prevent or reverse formation
of such amyloid deposits. We have recently described a number of di- and trisubstituted aromatic compounds that block the
formation of soluble oligomers and amyloid fibrils of the β-amyloid peptide (Aβ) and protect hippocampal neurons in culture
from Aβ-induced toxicity. Here, we show that some of those compounds inhibit the formation and disrupt preformed amyloid fibrils
from both human and hen egg white lysozyme. These results suggest that these small molecule compounds may serve as prototypes
for the development of drugs for the prevention or treatment of different types of amyloidoses. 相似文献
14.
有些天然蛋白质可通过错误折叠形成淀粉样纤维,并进一步沉积导致淀粉样病变,被认为是许多重大人类疾病的病理基础。因此,阐明天然蛋白质错误折叠、聚集形成淀粉样纤维的分子机制,是预防、诊断和治疗相关疾病的关键。研究者们从天然蛋白质中鉴定出许多能够形成淀粉样纤维的关键短肽片段,即淀粉样短肽,对它们形成淀粉样纤维的能力及其在完整蛋白质聚集过程中的决定性作用进行深入研究。本文对近年来人类疾病相关淀粉样短肽的研究展开综述。首先,介绍鉴定淀粉样短肽的标准及其相应的研究方法和技术手段;并回顾近年来与一些重大人类疾病相关的淀粉样短肽,尤其是与神经退行性疾病相关淀粉样短肽的进展情况,对淀粉样短肽中出现频率较高的氨基酸残基及其可能的自组装原理进行总结分析;最后,展望这些淀粉样短肽作为靶点在相关疾病诊断和治疗方面的意义,并初步探讨它们作为新型生物材料在生物医学工程领域的应用前景。本文一方面为阐明天然蛋白质形成淀粉样沉淀的分子机制提供参考,另一方面也为相关疾病的治疗提供思路,同时也为新型生物材料的开发提出潜在的可能性。 相似文献
15.
Carrotta R Barthès J Longo A Martorana V Manno M Portale G San Biagio PL 《European biophysics journal : EBJ》2007,36(7):701-709
Self-assembly of amyloid β-protein (Aβ) and its deposition into senile plaques are distinctive features of Alzheimer’s disease.
Aβ forms typical linear aggregates known as amyloid fibrils, with a diameter of a few tens of nanometers and a length spanning
from hundreds of nanometers to micrometers. Fibrils eventually assemble into large size clusters and precipitate in vivo in
the brain deposits. Here, we study the late stage of aggregation of Aβ(1–40) in vitro at pH 3.1. We characterize the structure
of fibrillar aggregates by a combined use of different experimental techniques. Small angle light scattering, heterodyne near
field scattering, large angle light scattering, ultra small angle X-ray scattering and small angle X-ray scattering measurements
have been performed to highlight the structural features of amyloid bundles over several lengthscales, from nanometers to
tens of micrometers. Phase contrast optical microscopy has been used to complement scattering measurements and directly visualize
some morphological details. We show that elongated fibrils of Aβ with a diameter of a few nanometers are packed into large
size compact bundles having a typical size of tens of micrometers. The linear morphology of fibrils is reflected in the elongated
shape of bundles.
Proceedings of the XVIII Congress of the Italian Society of Pure and Applied Biophysics (SIBPA), Palermo, Sicily, September
2006. 相似文献
16.
Francis C. Dehle Heath Ecroyd Ian F. Musgrave John A. Carver 《Cell stress & chaperones》2010,15(6):1013-1026
Amyloid fibril formation is associated with diseases such as Alzheimer’s, Parkinson’s, and prion diseases. Inhibition of amyloid
fibril formation by molecular chaperone proteins, such as the small heat-shock protein αB-crystallin, may play a protective
role in preventing the toxicity associated with this form of protein misfolding. Reduced and carboxymethylated κ-casein (RCMκ-CN),
a protein derived from milk, readily and reproducibly forms fibrils at physiological temperature and pH. We investigated the
toxicity of fibril formation by RCMκ-CN using neuronal model PC12 cells and determined whether the inhibition of fibril formation
altered its cell toxicity. To resolve ambiguities in the literature, we also investigated whether fibril formation by amyloid-β1–40
(Aβ1–40), the peptide associated with Alzheimer’s disease, was inhibited by αB-crystallin and if this affected the toxicity of Aβ.
To this end, either RCMκ-CN or Aβ1–40 was incubated at neutral pH to induce fibril formation before treating PC12 cells and assessing cell viability. Incubated
(fibrillar) RCMκ-CN was more toxic to PC12 cells than native RCMκ-CN with the highest level of toxicity being associated with
mature fibrils and protofibrils. Furthermore, the toxicity of RCMκ-CN was attenuated when its fibril formation was inhibited,
either through the chaperone action of αB-crystallin or when it interacted with its natural binding partners in milk, αS- and β-casein. Likewise, incubating Aβ1–40 with αB-crystallin inhibited both Aβ1–40 fibril formation and the associated cell toxicity. Importantly, by inhibiting fibril formation, αB-crystallin prevents the
cell toxicity associated with protein misfolding. 相似文献
17.
Redondo C Damas AM Olofsson A Lundgren E Saraiva MJ 《Journal of molecular biology》2000,304(3):461-470
Familial Amyloidotic Polyneuropathy (FAP) is caused by the assembly of TTR into an insoluble beta-sheet. The TTR tetramer is thought to dissociate into monomeric intermediates and subsequently polymerise into the pathogenic amyloid form. The biochemical mechanism behind this transformation is unknown. We characterised intermediate TTR structures in the in vitro amyloidogenesis pathway by destabilising the AB loop through substitution of residue 78. Changes at this residue, should destabilise the TTR tetrameric fold, based on the known crystallographic structure of a Leu55Pro transthyretin variant. We generated a soluble tetrameric form of TTR that is recognised by a monoclonal antibody, previously reported to react only with highly amyloidogenic mutant proteins lacking the tetrameric native fold and with amyloid fibrils. BIAcore system analysis showed that Tyr78Phe had similar binding properties as synthetic fibrils. The affinity of this interaction was 10(7) M(-1). We suggest that the tetrameric structure of Tyr78Phe is altered due to the loosening of the AB loops of the tetramer, leading to a structure that might represent an early intermediate in the fibrillogenesis pathway. 相似文献
18.
Sundaram RK Kasinathan C Stein S Sundaram P 《International journal of peptide research and therapeutics》2012,18(2):99-106
Alzheimer’s disease (AD), a debilitating neurodegenerative disease is caused by aggregation and accumulation of a 39–43 amino
acid peptide (amyloid β or Aβ) in brain parenchyma and cerebrovasculature. The rational approach would be to use drugs that
interfere with Aβ–Aβ interaction and disrupt polymerization. Peptide ligands capable of binding to the KLVFF (amino acids
16–20) region in the Aβ molecule have been investigated as possible drug candidates. Retro-inverso (RI) peptide of this pentapeptide,
ffvlk, has been shown to bind artificial fibrils made from Aβ with moderate affinity. We hypothesized that a ‘detox gel’, which
is synthesized by covalently linking a tetrameric version of RI peptide ffvlk to poly(ethylene glycol) polymer chains will act like a ‘sink’ to capture Aβ peptides from the surrounding environment. We
previously demonstrated that this hypothesis works in an in vitro system. The present study extended this hypothesis to an
in vivo mouse model of AD and determined the therapeutic effect of our detox gel. We injected detox gel subcutaneously to
AD model mice and analyzed brain levels of Aβ-42 and improvement in memory parameters. The results showed a reduction of brain
amyloid burden in detox gel treated mice. Memory parameters in the treated mice improved. No undesirable immune response was
observed. The data strongly suggest that our detox gel can be used as an effective therapy to deplete brain Aβ levels. Considering
recent abandonment of failed antibody based therapies, our detox gel appears to have the advantage of being a non-immune based
therapy. 相似文献
19.
Christine Talmard Rodrigue Leuma Yona Peter Faller 《Journal of biological inorganic chemistry》2009,14(3):449-455
The amyloidoses are a group of disorders characterized by aberrant protein folding and assembly, leading to the deposition
of insoluble protein fibrils (amyloid), which provokes cell dysfunction and later cell death. One of the physiologically relevant
environmental factors able to affect the conformation and hence the aggregation properties of amyloidogenic proteins/peptides
is metal ions. Zn(II) promotes aggregation of most amyloidogenic peptides/proteins in vitro, including amyloid β protein (Aβ),
but the underlying mechanism is not known. To better understand this mechanism the present study focused on the partially
α-helical conformer, supposed to be an intermediate in Aβ aggregation. This partially α-helical conformer is stabilized by
10–20% 2,2,2-trifluoroethanol (TFE): therefore, the influence of Zn binding on the aggregation of the amylidogenic model peptide
Aβ(1–28) (Aβ28) was investigated at different TFE concentrations. The results showed a synergistic effect of Zn(II) and 10%
TFE, i.e., that either Zn or 10% TFE accelerated Aβ28 aggregation on its own, but with them together an at least 10 times
promotion of Aβ28 aggregation was observed. Further studies by thioflavin T fluorescence spectroscopy, transmission electron
microscopy, and circular dichroism (CD) spectroscopy suggested that the aggregates of Zn-Aβ28 formed in 10%TFE contain a β-sheet
secondary structure and are more of the amyloid type. CD spectroscopy indicated that Zn binding disrupted partially the α-helical
structure of Aβ28 in TFE. Thus, we propose that the promotion of Aβ28 aggregation by Zn is based on the transformation of
the partially α-helical conformer (intermediate) towards the β-sheet amyloid structure by a destabilization of the α-helix
in the intermediate.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
相似文献
Peter FallerEmail: Email: |
20.
Krebs MR Wilkins DK Chung EW Pitkeathly MC Chamberlain AK Zurdo J Robinson CV Dobson CM 《Journal of molecular biology》2000,300(3):541-549
Wild-type hen lysozyme has been converted from its soluble native state into highly organized amyloid fibrils. In order to achieve this conversion, conditions were chosen to promote partial unfolding of the native globular fold and included heating of low-pH solutions and addition of organic solvents. Two peptides derived from the beta-sheet region of hen lysozyme were also found to form fibrils very readily. The properties and morphologies of the amyloid fibrils formed by incubation either of the protein or the peptides are similar to those produced from the group of proteins associated with clinical amyloidoses. Fibril formation by hen lysozyme was substantially accelerated when aliquots of solutions in which fibrils of either one of the peptides or the full-length protein had previously formed were added to fresh solutions of the protein, revealing the importance of seeding in the kinetics of fibril formation. These findings support the proposition that the beta-domain is of particular significance in the formation of fibrils from the full-length protein and suggest similarities between the species giving rise to fibril formation and the intermediates formed during protein folding. 相似文献