NMR structure of temporin-1 ta in lipopolysaccharide micelles: mechanistic insight into inactivation by outer membrane.

Background: Antimicrobial peptides (AMPs) play important roles in the innate defense mechanism. The broad spectrum of activity of AMPs requires an efficient permeabilization of the bacterial outer and inner membranes. The outer leaflet of the outer membrane of Gram negative bacteria is made of a specialized lipid called lipopolysaccharide (LPS).

Structure, activity and interactions of the cysteine deleted analog of tachyplesin-1 with lipopolysaccharide micelle: Mechanistic insights into outer-membrane permeabilization and endotoxin neutralization.

Tachyplesin-1, a disulfide stabilized beta-hairpin antimicrobial peptide, can be found at the hemocytes of horse shoe crab Tachypleus tridentatus. A cysteine deleted linear analog of tachyplesin-1 or CDT (KWFRVYRGIYRRR-NH2) contains a broad spectrum of bactericidal activity with a reduced hemolytic property. The bactericidal activity of CDT stems from selective interactions with the negatively charged lipids including LPS.

Small molecule AKAP-protein kinase A (PKA) interaction disruptors that activate PKA interfere with compartmentalized cAMP signaling in cardiac myocytes.

A-kinase anchoring proteins (AKAPs) tether protein kinase A (PKA) and other signaling proteins to defined intracellular sites, thereby establishing compartmentalized cAMP signaling. AKAP-PKA interactions play key roles in various cellular processes, including the regulation of cardiac myocyte contractility. We discovered small molecules, 3,3'-diamino-4,4'-dihydroxydiphenylmethane (FMP-API-1) and its derivatives, which inhibit AKAP-PKA interactions in vitro and in cultured cardiac myocytes.

Glycogen synthase kinase 3beta interaction protein functions as an A-kinase anchoring protein.

A-kinase anchoring proteins (AKAPs) include a family of scaffolding proteins that target protein kinase A (PKA) and other signaling proteins to cellular compartments and thereby confine the activities of the associated proteins to distinct regions within cells. AKAPs bind PKA directly. The interaction is mediated by the dimerization and docking domain of regulatory subunits of PKA and the PKA-binding domain of AKAPs.

Homophilic interactions of the amyloid precursor protein (APP) ectodomain are regulated by the loop region and affect beta-secretase cleavage of APP.

We found previously by fluorescence resonance energy transfer experiments that amyloid precursor protein (APP) homodimerizes in living cells. APP homodimerization is likely to be mediated by two sites of the ectodomain and a third site within the transmembrane sequence of APP. We have now investigated the role of the N-terminal growth factor-like domain in APP dimerization by NMR, biochemical, and cell biological approaches.

Morphology-associated expression of NADP-dependent glutamate dehydrogenases during yeast-mycelium transition of a dimorphic fungus Benjaminiella poitrasii.

Benjaminiella poitrasii, a dimorphic zygomycetous fungus possesses three glutamate dehydrogenases, one requiring NAD while the other two use NADP as a coenzyme. In the activity staining after electrophoresis on native polyacrylamide gel NAD- dependent glutamate dehydrogenase revealed the presence of one enzyme that was expressed in both, yeast- and mycelium-form cells. While in case of NADP- dependent glutamate dehydrogenase two distinct activity bands that were differentially expressed in yeast- and mycelium-form cells were seen.