Louise C Serpell

University of Sussex, Brighton, England, United Kingdom

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Publications (102)571.11 Total impact

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    ABSTRACT: Low molecular weight hydrogels are formed by molecules that form a matrix that immobilises water to form a self-supporting gel. Such gels have uses as biomaterials such as molecular scaffolds and structures for tissue engineering. One class of low molecular weight gelators (LMWG), naphthalene-conjugated dipeptides, has been shown to form hydrogels via self-assembly following a controlled drop in pH. A library of naphthalene-dipeptides has been generated previously although the relationship between the precursor sequence and the resulting self-assembled structures remained unclear. Here, we have investigated the structural details of a set of dipeptide sequences containing alanine (A) and valine (V) conjugated to naphthalene groups substituted with a Br, CN or H at the 6-position. Electron microscopy, circular dichroism and X-ray fibre diffraction shows that these LMWG may be structurally classified by their composition: the molecular packing is determined by the class of conjugate, whilst the chirality of the self-assemblies can be attributed to the dipeptide sequence. This provides insights into the relationship between the precursor sequence and the macromolecular and molecular structures of the fibres that make up the resulting hydrogels.
    Soft Matter 12/2014; · 4.15 Impact Factor
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    ABSTRACT: Self-sorting in low molecular weight hydrogels can be achieved using a pH triggered approach. We show here that this method can be used to prepare gels with different types of mechanical properties. Cooperative, disruptive or orthogonal assembled systems can be produced. Gels with interesting behaviour can be also prepared, for example self-sorted gels where delayed switch-on of gelation occurs. By careful choice of gelator, co-assembled structures can also be generated, which leads to synergistic strengthening of the mechanical properties.
    Nanoscale 09/2014; · 6.74 Impact Factor
  • Louise Serpell
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    ABSTRACT: Amyloid fibrils are formed by numerous proteins and peptides that share little sequence homology. The structures formed are highly ordered and extremely stable, being composed of β-sheet structure and stabilized along their length by hydrogen bonding. The fibrils are formed by several protofilaments that wind around one another in rope-like structures, lending further strength and stability to the resulting fibres. The fact that so many proteins and peptides form amyloid structures under suitable conditions, seems to suggest that the sequence of the precursor is unimportant. However, it is now clear that side chains play a central role in forming interactions between several β-sheets to further stabilize and regulate the structures. The primary sequence plays a central role in determining the rate of fibril formation, the stability of the resulting structure to degradation and the final morphology of the fibrils. The side chains regulate the elongation and growth, and also the lateral association of the protofilament and fibrils, having a significant impact on the final architecture.
    Essays in Biochemistry 08/2014; 56(1):1-10. · 4.39 Impact Factor
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    Thomas L Williams, Louise C Serpell
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    ABSTRACT: Prion-like propagation of tau aggregation might underlie the stereotyped progression of neurodegenerative tauopathies. True prions stably maintain unique conformations ("strains") in vivo that link structure to patterns of pathology. We now find that tau meets this criterion. Stably expressed tau repeat domain indefinitely propagates distinct amyloid conformations in a clonal fashion in culture. Reintroduction of tau from these lines into naive cells reestablishes identical clones. We produced two strains in vitro that induce distinct pathologies in vivo as determined by successive inoculations into three generations of transgenic mice. Immunopurified tau from these mice recreates the original strains in culture. We used the cell system to isolate tau strains from 29 patients with 5 different tauopathies, finding that different diseases are associated with different sets of strains. Tau thus demonstrates essential characteristics of a prion. This might explain the phenotypic diversity of tauopathies and could enable more effective diagnosis and therapy.
    Neuron 05/2014; · 15.77 Impact Factor
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    ABSTRACT: Self-assembly of proteins and peptides into amyloid structures has been the subject of intense and focused research due to their association with neurodegenerative, age-related human diseases and transmissible prion diseases in humans and mammals. Of the disease associated amyloid assemblies, a diverse array of species, ranging from small oligomeric assembly intermediates to fibrillar structures, have been shown to have toxic potential. Equally, a range of species formed by the same disease associated amyloid sequences have been found to be relatively benign under comparable monomer equivalent concentrations and conditions. In recent years, an increasing number of functional amyloids have also been found. These developments show that not all amyloid structures are generically toxic to cells. Given these observations, it is important to understand why amyloid structures may encode such varied toxic potential despite sharing a common core molecular architecture. Here, we discuss possible links between different aspects of amyloidogenic structures and assembly mechanisms with their varied functional effects. We propose testable hypotheses for the relationship between amyloid structure and its toxic potential in the context of recent reports on amyloid sequence, structure, and toxicity relationships.
    Prion 05/2014; 8(2). · 1.97 Impact Factor
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    ABSTRACT: The Ser52Pro variant of transthyretin (TTR) produces aggressive, highly penetrant, autosomal-dominant systemic amyloidosis in persons heterozygous for the causative mutation. Together with a minor quantity of full-length wild-type and variant TTR, the main component of the ex vivo fibrils was the residue 49-127 fragment of the TTR variant, the portion of the TTR sequence that previously has been reported to be the principal constituent of type A, cardiac amyloid fibrils formed from wild-type TTR and other TTR variants [Bergstrom J, et al. (2005) J Pathol 206(2):224-232]. This specific truncation of Ser52Pro TTR was generated readily in vitro by limited proteolysis. In physiological conditions and under agitation the residue 49-127 proteolytic fragment rapidly and completely self-aggregates into typical amyloid fibrils. The remarkable susceptibility to such cleavage is likely caused by localized destabilization of the β-turn linking strands C and D caused by loss of the wild-type hydrogen-bonding network between the side chains of residues Ser52, Glu54, Ser50, and a water molecule, as revealed by the high-resolution crystallographic structure of Ser52Pro TTR. We thus provide a structural basis for the recently hypothesized, crucial pathogenic role of proteolytic cleavage in TTR amyloid fibrillogenesis. Binding of the natural ligands thyroxine or retinol-binding protein (RBP) by Ser52Pro variant TTR stabilizes the native tetrameric assembly, but neither protected the variant from proteolysis. However, binding of RBP, but not thyroxine, inhibited subsequent fibrillogenesis.
    Proceedings of the National Academy of Sciences 01/2014; 111(4):1539-44. · 9.81 Impact Factor
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    ABSTRACT: Alzheimer's disease (AD) is characterized by the deposition of insoluble amyloid plaques in the neuropil composed of highly stable, self-assembled Amyloid-beta (Abeta) fibrils. Copper has been implicated to play a role in Alzheimer's disease. Dimers of Abeta have been isolated from AD brain and have been shown to be neurotoxic. We have investigated the formation of dityrosine cross-links in Abeta42 formed by covalent ortho-ortho coupling of two tyrosine residues under conditions of oxidative stress with elevated copper and shown that dityrosine can be formed in vitro in Abetaoligomers and fibrils and that these links further stabilize the fibrils. Dityrosine crosslinking was present in internalized Abeta in cell cultures treated with oligomeric Abeta42 using a specific antibody for dityrosine by immunogold labeling transmission electron microscopy. Results also revealed the prevalence of dityrosine crosslinks in amyloid plaques in brain tissue and in cerebrospinal fluid from AD patients. Abeta dimers may be stabilized by dityrosine crosslinking. These results indicate that dityrosine cross-links may play an important role in the pathogenesis of Alzheimer's disease and can be generated by reactive oxygen species catalyzed by Cu2+ ions. The observation of increased Abeta and dityrosine in CSF from AD patients suggests that this could be used as a potential biomarker of oxidative stress in AD.
    Acta neuropathologica communications. 12/2013; 1(1):83.
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    ABSTRACT: The design of a structurally defined helical assembly is described that involves recoding of the amino acid sequence of peptide GCN4-pAA. In solution and the crystalline state, GCN4-pAA adopts a 7-helix bundle structure that resembles a supramolecular lock-washer. Structurally informed mutagenesis of the sequence of GCN4-pAA afforded peptide 7HSAP1, which undergoes self-association into a nanotube via non-covalent interactions between complementary interfaces of the coiled-coil lock washer structures. Biophysical measurements conducted in solution and the solid-state over multiple length-scales of structural hierarchy are consistent with the self-assembly of nanotube structures derived from the 7-helix bundle sub-units, in which the dimensions of the supramolecular assemblies are similar to those observed in the crystal structure of GCN4-pAA. Fluorescence studies of the interaction of 7HSAP1 with the solvatochromic fluorophore PRODAN indicated that the nanotubes could encapsulate shape-appropriate small-molecules with high binding affinity.
    Journal of the American Chemical Society 09/2013; · 11.44 Impact Factor
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    ABSTRACT: Controlling the order and spatial distribution of self-assembly in multicomponent supramolecular systems could underpin exciting new functional materials, but it is extremely challenging. When a solution of different components self-assembles, the molecules can either coassemble, or self-sort, where a preference for like-like intermolecular interactions results in coexisting, homomolecular assemblies. A challenge is to produce generic and controlled 'one-pot' fabrication methods to form separate ordered assemblies from 'cocktails' of two or more self-assembling species, which might have relatively similar molecular structures and chemistry. Self-sorting in supramolecular gel phases is hence rare. Here we report the first example of the pH-controlled self-sorting of gelators to form self-assembled networks in water. Uniquely, the order of assembly can be predefined. The assembly of each component is preprogrammed by the pK(a) of the gelator. This pH-programming method will enable higher level, complex structures to be formed that cannot be accessed by simple thermal gelation.
    Nature Communications 02/2013; 4:1480. · 10.74 Impact Factor
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    ABSTRACT: Elaborate morphology: The αSβ1 peptide, a fragment of α-synuclein, assembles into flat tapes consisting of a peptide bilayer, which can be modeled based on the cross-β structure found in amyloid proteins. The tapes are stabilized by hydrogen bonding, whilst the amphiphilic nature of the peptide results in the thin bilayer structure. To further stabilize the structure, these tapes may twist to form helical tapes, which subsequently close into nanotubes.
    Angewandte Chemie International Edition 01/2013; · 11.34 Impact Factor
  • K. L. Morris, L. Serpell
    01/2013; Viley-VCH.
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    ABSTRACT: Amyloid fibril formation is associated with misfolding diseases, as well as fulfilling a functional role. The cross-ß molecular architecture has been reported in increasing numbers of amyloid-like fibrillar systems. The Waltz algorithm is able to predict ordered self-assembly of amyloidogenic peptides by taking into account residue type and position. This algorithm has expanded the amyloid sequence space and here we characterise the structures of amyloid-like fibrils formed by three peptides identified by Waltz that form fibrils but not crystals. The structural challenge is met by combining electron microscopy, linear and circular dichroism and X-ray fibre diffraction. We propose structures that reveal a cross-ß conformation with 'steric-zipper' features, giving insights into the role for side chains in peptide packing and stability within fibrils. The amenity of these peptides to structural characterisation makes them compelling model systems to use for understanding the relationship between sequence, self-assembly, stability and structure for amyloid fibrils.
    Biochemical Journal 12/2012; · 4.78 Impact Factor
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    ABSTRACT: Coherent anti-Stokes Raman scattering (CARS) microscopy is applied for the first time for the evaluation of the protein secondary structure of polyglutamine (polyQ) aggregates in vivo. Our approach demonstrates the potential for translating information about protein structure that has been obtained in vitro by X-ray diffraction into a microscopy technique that allows the same protein structure to be detected in vivo. For these studies, fibres of polyQ containing peptides (D(2)Q(15)K(2)) were assembled in vitro and examined by electron microscopy and X-ray diffraction methods; the fibril structure was shown to be cross β-sheet. The same polyQ fibres were evaluated by Raman spectroscopy and this further confirmed the β-sheet structure, but indicated that the structure is highly rigid, as indicated by the strong Amide I signal at 1659 cm(-1). CARS spectra were simulated using the Raman spectrum taking into account potential non-resonant contributions, providing evidence that the Amide I signal remains strong, but slightly shifted to lower wavenumbers. Combined CARS (1657 cm(-1)) and multi-photon fluorescence microscopy of chimeric fusions of yellow fluorescent protein (YFP) with polyQ (Q40) expressed in the body wall muscle cells of Caenorhabditis elegans nematodes (1 day old adult hermaphrodites) revealed diffuse and foci patterns of Q40-YFP that were both fluorescent and exhibited stronger CARS (1657 cm(-1)) signals than in surrounding tissues at the resonance for the cross β-sheet polyQ in vitro.
    PLoS ONE 07/2012; 7(7):e40536. · 3.53 Impact Factor
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    ABSTRACT: Naphthalene dipeptides have been shown to be useful low-molecular-weight gelators. Here we have used a library to explore the relationship between the dipeptide sequence and the hydrogelation efficiency. A number of the naphthalene dipeptides are crystallizable from water, enabling us to investigate the comparison between the gel/fiber phase and the crystal phase. We succeeded in crystallizing one example directly from the gel phase. Using X-ray crystallography, molecular modeling, and X-ray fiber diffraction, we show that the molecular packing of this crystal structure differs from the structure of the gel/fiber phase. Although the crystal structures may provide important insights into stabilizing interactions, our analysis indicates a rearrangement of structural packing within the fibers. These observations are consistent with the fibrillar interactions and interatomic separations promoting 1D assembly whereas in the crystals the peptides are aligned along multiple axes, allowing 3D growth. This observation has an impact on the use of crystal structures to determine supramolecular synthons for gelators.
    Langmuir 05/2012; 28(25):9797-806. · 4.38 Impact Factor
  • Kyle L Morris, Louise C Serpell
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    ABSTRACT: Amyloid fibrils are polymeric assemblies of normally soluble proteins or peptides. To investigate their structure, it is generally not possible to use conventional methods of crystallography and solution nuclear magnetic resonance. To examine the repeating crystalline structure along the fibre axis, X-ray fibre diffraction has been a useful tool. Here we discuss the methods by which amyloid-like fibrils may be prepared to form a sample suitable for structural analysis and describe how data may be collected and then analysed to arrive at a potential model structure.
    Methods in molecular biology (Clifton, N.J.) 01/2012; 849:121-35. · 1.29 Impact Factor
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    Biochemical Journal 01/2012; 441:579-590. · 4.78 Impact Factor
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    ABSTRACT: The β-amyloid peptide (Aβ) is directly related to neurotoxicity in Alzheimer disease (AD). The two most abundant alloforms of the peptide co-exist under normal physiological conditions in the brain in an Aβ(42):Aβ(40) ratio of ∼1:9. This ratio is often shifted to a higher percentage of Aβ(42) in brains of patients with familial AD and this has recently been shown to lead to increased synaptotoxicity. The molecular basis for this phenomenon is unclear. Although the aggregation characteristics of Aβ(40) and Aβ(42) individually are well established, little is known about the properties of mixtures. We have explored the biophysical and structural properties of physiologically relevant Aβ(42):Aβ(40) ratios by several techniques. We show that Aβ(40) and Aβ(42) directly interact as well as modify the behavior of the other. The structures of monomeric and fibrillar assemblies formed from Aβ(40) and Aβ(42) mixtures do not differ from those formed from either of these peptides alone. Instead, the co-assembly of Aβ(40) and Aβ(42) influences the aggregation kinetics by altering the pattern of oligomer formation as evidenced by a unique combination of solution nuclear magnetic resonance spectroscopy, high molecular weight mass spectrometry, and cross-seeding experiments. We relate these observations to the observed enhanced toxicity of relevant ratios of Aβ(42):Aβ(40) in synaptotoxicity assays and in AD patients.
    Journal of Biological Chemistry 12/2011; 287(8):5650-60. · 4.60 Impact Factor
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    ABSTRACT: Addition of divalent cations to a solution of a naphthalene-diphenylalanine that forms worm-like micelles at high pH results in the formation of a rigid, self-supporting hydrogel.
    Chemical Communications 11/2011; 47(44):12071-3. · 6.38 Impact Factor

Publication Stats

5k Citations
571.11 Total Impact Points


  • 2005–2014
    • University of Sussex
      • School of Life Sciences
      Brighton, England, United Kingdom
  • 2010–2012
    • University of Liverpool
      • Department of Chemistry
      Liverpool, ENG, United Kingdom
    • Vrije Universiteit Brussel
      Bruxelles, Brussels Capital Region, Belgium
  • 2000–2009
    • University of Cambridge
      • • Department of Chemistry
      • • Cambridge Institute for Medical Research
      • • Department of Haematology
      • • MRC Laboratory of Molecular Biology
      Cambridge, ENG, United Kingdom
  • 2008
    • Universität Basel
      Bâle, Basel-City, Switzerland
  • 2007
    • University of Brighton
      Brighton, England, United Kingdom
  • 2006
    • University of Leeds
      • Astbury Centre for Structural Molecular Biology (ACSMB)
      Leeds, ENG, United Kingdom
  • 2003
    • University of Bristol
      • School of Physics
      Bristol, ENG, United Kingdom
  • 2001–2002
    • Cambridge Institute for Medical Research
      Cambridge, England, United Kingdom
    • University of Toronto
      • Tanz Centre for Research in Neurodegenerative Diseases
      Toronto, Ontario, Canada
  • 1998–2001
    • University of Oxford
      • • Chemical Research Laboratory
      • • Department of Biochemistry
      Oxford, ENG, United Kingdom
  • 1999–2000
    • Medical Research Council (UK)
      • • Division of Neurobiology
      • • MRC Laboratory of Molecular Biology
      London, ENG, United Kingdom