Rational Design of Phosphorylation-Responsive Coiled Coil-Peptide Assemblies.

De novo peptides and proteins that switch state in response to chemical and physical cues would advance protein design and synthetic biology. Here we report two designed systems that disassemble and reassemble upon site-specific phosphorylation and dephosphorylation, respectively. As starting points, we use hyperthermostable de novo antiparallel and parallel coiled-coil heterotetramers, i.e., A2B2 systems, to afford control in downstream applications. The switches are incorporated by adding protein kinase A phosphorylation sites, R-R-X-S, with the phosphoacceptor serine residues placed to maximize disruption of the coiled-coil interfaces. The unphosphorylated peptides assemble as designed and unfold reversibly when heated. Addition of kinase to the assembled states unfolds them with half-lives of ≤5 min. Phosphorylation is reversed by Lambda Protein Phosphatase resulting in tetramer reassembly. We envisage that the new de novo designed coiled-coil components, the switches, and a mechanistic model for them will be useful in synthetic biology, biomaterials, and biotechnology applications.

De novo designed peptides for cellular delivery and subcellular localisation.

Increasingly, it is possible to design peptide and protein assemblies de novo from first principles or computationally. This approach provides new routes to functional synthetic polypeptides, including designs to target and bind proteins of interest. Much of this work has been developed in vitro. Therefore, a challenge is to deliver de novo polypeptides efficiently to sites of action within cells. Here we describe the design, characterisation, intracellular delivery, and subcellular localisation of a de novo synthetic peptide system. This system comprises a dual-function basic peptide, programmed both for cell penetration and target binding, and a complementary acidic peptide that can be fused to proteins of interest and introduced into cells using synthetic DNA. The designs are characterised in vitro using biophysical methods and X-ray crystallography. The utility of the system for delivery into mammalian cells and subcellular targeting is demonstrated by marking organelles and actively engaging functional protein complexes.

Assessing remission in major depressive disorder and generalized anxiety disorder clinical trials with the discan metric of the Sheehan disability scale.

Relatively little research has focused on the relationship between functional remission and symptomatic remission in mood and anxiety disorders. This study investigates the relationship and synchrony between symptomatic and functional remission in outpatients with major depressive disorder (MDD) and generalized anxiety disorder (GAD). Using data from three MDD (N=1419) and four GAD (N=1847) randomized, placebo-controlled duloxetine studies, we calculated the percentages of patients meeting symptomatic, functional, and combined functional-symptomatic remission criteria for each disorder. We also calculated mean depression [17-item Hamilton depression rating scale (HAMD17), Montgomery-Asberg depression rating scale] scores and mean anxiety (Hamilton anxiety rating scale) scores for patients meeting Sheehan disability scale (SDS) functional remission and the mean SDS scores for patients with symptomatic remission. Among the patients with MDD, 38% achieved symptomatic remission (HAMD17 ≤ 7), 32% achieved functional remission (SDS ≤ 6), and 23% achieved combined functional-symptomatic remission. Mean HAMD17 and Montgomery-Asberg depression rating scale scores for patients with functional remission were approximately 6. Mean SDS total scores for patients with symptomatic remission were 7.1 (patients with HAMD17 ≤ 7) and 8.6 (patients with Montgomery-Asberg depression rating scale ≤ 10). Among the patients with GAD, 30% achieved symptomatic remission (Hamilton anxiety rating scale ≤ 7), 45% achieved functional remission (SDS ≤ 6), and 25% achieved combined symptomatic-functional remission. The mean Hamilton anxiety rating scale score in GAD was approximately 8 for patients with functional remission and the mean SDS total score was approximately 4 in patients with symptomatic remission. The study shows that functional remission does not always move in tandem with symptom remission and provides useful anchor points or rules of thumb for evaluating symptomatic and functional remission in MDD and GAD.