Further assessments of ligase LplA-mediated modifications of proteins in vitro and in cellulo.

Background: Posttranslational modifications of proteins are catalyzed by a large family of enzymes catalyzing many chemical modifications. One can hijack the natural use of those enzymes to modify targeted proteins with synthetic chemical moieties. The lipoic acid ligase LplA mutants can be used to introduce onto the lysine sidechain lipoic acid moiety synthetic analogues.

Raman Imaging Reveals Accumulation of Hemoproteins in Plaques from Alzheimer's Diseased Tissues.

Hemes have been suggested to play a central role in Alzheimer's disease since they show high peroxidase reactivity when bound to amyloid β peptides, leading to the production of reactive oxygen species. Here we used Fourier transform infrared and Raman imaging on Alzheimer's diseased mice and human brain tissue. Our finding suggests the accumulation of hemes in the senile plaques of both murine and human samples.

Vectofusin-1, a potent peptidic enhancer of viral gene transfer forms pH-dependent α-helical nanofibrils, concentrating viral particles.

Gene transfer using lentiviral vectors has therapeutic applications spanning from monogenic and infectious diseases to cancer. Such gene therapy has to be improved by enhancing the levels of viral infection of target cells and/or reducing the amount of lentivirus for greater safety and reduced costs. Vectofusin-1, a recently developed cationic amphipathic peptide with a pronounced capacity to enhance such viral transduction, strongly promotes the entry of several retroviral pseudotypes into target cells when added to the culture medium.

Similarities and differences of copper and zinc cations binding to biologically relevant peptides studied by vibrational spectroscopies.

GHK and DAHK are biological peptides that bind both copper and zinc cations. Here we used infrared and Raman spectroscopies to study the coordination modes of both copper and zinc ions, at pH 6.8 and 8.

Covalent Tethering and Residues with Bulky Hydrophobic Side Chains Enable Self-Assembly of Distinct Amyloid Structures.

Polymorphism is a common property of amyloid fibers that complicates their detailed structural and functional studies. Here we report experiments illustrating the chemical principles that enable the formation of amyloid polymorphs with distinct stoichiometric composition. Using appropriate covalent tethering we programmed self-assembly of a model peptide corresponding to the [20-41] fragment of human β2-microglobulin into fibers with either trimeric or dimeric amyloid cores.

Chiral recognition in amyloid fiber growth.

Insoluble amyloid fibers represent a pathological signature of many human diseases. To treat such diseases, inhibition of amyloid formation has been proposed as a possible therapeutic strategy. d-Peptides, which possess high proteolytic stability and lessened immunogenicity, are attractive candidates in this context.