Serine 408 phosphorylation is a molecular switch that regulates structure and function of the occludin α-helical bundle.

Occludin is a tetramembrane-spanning tight junction protein. The long C-terminal cytoplasmic domain, which represents nearly half of occludin sequence, includes a distal bundle of three α-helices that mediates interactions with other tight junction components. A short unstructured region just proximal to the α-helical bundle is a phosphorylation hotspot within which S408 phosphorylation acts as molecular switch that modifies tight junction protein interactions and barrier function.

Nanodroplet Oligomers (NanDOs) of Aβ40.

Using atomic force microscopy (AFM) and nuclear magnetic resonance (NMR), we describe small Aβ40 oligomers, termed nanodroplet oligomers (NanDOs), which form rapidly and at Aβ40 concentrations too low for fibril formation. NanDOs were observed in putatively monomeric solutions of Aβ40 (e.g.

A versatile method for producing labeled or unlabeled Aβ55, Aβ40, and other β-amyloid family peptides.

We present a straightforward, versatile method for expressing and purifying β-amyloid (Aβ40) and transmembrane peptides derived from β-amyloid precursor protein (Aβ55). In principle, these methods should be applicable to other types of strongly aggregating peptides. We start with a DNA plasmid encoding a HexaHis tag with a flexible, hydrophilic linker sequence, followed by a cleavage site, and then Aβ peptides.

A Focal Adhesion Kinase-Derived Peptide Binds the Src SH3 Domain in Two Orientations, As Demonstrated Using Paramagnetic Nuclear Magnetic Resonance.

SH3 binding peptides contain polyproline helices and are classified according to their binding orientations as N-to-C-terminal or C-to-N-terminal. We have tested the hypothesis that such a peptide binds in both orientations but with different populations. A focal adhesion kinase (FAK)-derived peptide was tested for its binding orientation on the Src SH3 domain.

The cataract-associated V41M mutant of human γS-crystallin shows specific structural changes that directly enhance local surface hydrophobicity.

The major crystallins expressed in the human lens are γS-, γC- and γD-crystallins. Several mutations in γS-crystallin are associated with hereditary cataracts, one of which involves the substitution of a highly conserved Valine at position 41 to Methionine. According to a recent report, the mutant protein, V41M, shows lower stability and increased surface hydrophobicity compared to the wild-type, and a propensity for self-aggregation.

Structural basis for the functional and inhibitory mechanisms of β-hydroxyacyl-acyl carrier protein dehydratase (FabZ) of Plasmodium falciparum.

The β-hydroxyacyl-acyl carrier protein dehydratase of Plasmodium falciparum (PfFabZ) catalyzes the third and important reaction of the fatty acid elongation cycle. The crystal structure of PfFabZ is available in hexameric (active) and dimeric (inactive) forms. However, PfFabZ has not been crystallized with any bound inhibitors until now.

Linker length dependent binding of a focal adhesion kinase derived peptide to the Src SH3-SH2 domains.

The interaction between a peptide encompassing the SH3 and SH2 binding motifs of focal adhesion kinase (FAK) and the Src SH3-SH2 domains has been investigated with NMR spectroscopy and calorimetry. The binding to both motifs is anti-cooperative. Reduction of the long linker connecting the motifs does not lead to cooperativity.