Engineering and optimization of an allosteric biosensor protein for peroxisome proliferator-activated receptor γ ligands.

The peroxisome proliferator-activated receptor gamma (PPARγ or PPARG) belongs to the nuclear receptor superfamily, and is a potential drug target for a variety of diseases. In this work, we constructed a series of bacterial biosensors for the identification of functional PPARγ ligands. These sensors entail modified Escherichia coli cells carrying a four-domain fusion protein, comprised of the PPARγ ligand binding domain (LBD), an engineered mini-intein domain, the E.

Self-cleaving purification tags re-engineered for rapid Topo® cloning.

In this work, our previously reported ΔI-CM and ΔI(G)-CM mutant inteins were rationally re-engineered to be compatible with Invitrogen's Topo® cloning system. The resulting new inteins include the vaccinia virus topoisomerase I DNA recognition sequence TCCTT at their 3' ends, making them compatible with the highly convenient one-step Topo® cloning method. Addition of the Topo® recognition sequence resulted in an altered amino acid sequence at the C-termini of the inteins, changing their final five residues from VVVHN to VLVHN.

Purification of Escherichia coli RNA polymerase using a self-cleaving elastin-like polypeptide tag.

A self-cleaving elastin-like polypeptide (ELP) tag was used to purify the multisubunit Escherichia coli RNA polymerase (RNAP) via a simple, nonchromatographic method. To accomplish this, the RNAP alpha subunit was tagged with a self-cleaving ELP-intein tag and coexpressed with the beta, beta', and omega subunits. The assembled RNAP was purified with its associated subunits, and was active and acquired at reasonable yield and purity.

Application of screening methods, shape signatures and engineered biosensors in early drug discovery process.

Purpose: In this study, two unreported estrogen antagonists were identified using a combination of computational screening and a simple bacterial estrogen sensor.

Methods: Molecules here presented were initially part of a group obtained from a library of over a half million chemical compounds, using the Shape Signatures method. The structures within this group were then clustered and compared to known antagonists based on their physico-chemical parameters, and possible binding modes of the compounds to the Estrogen Receptor alpha (ER alpha) were analyzed.

PHB-intein-mediated protein purification strategy.

A method has been developed that eliminates the need for complex chromatographic apparatus in the purification of recombinant proteins expressed in Escherichia coli. This method is similar to conventional affinity-tag separations, but the affinity resin is replaced by polyhydroxybutyrate (PHB) particles prodced in vivo in the E. coli expression host during protein expression.

Rapid cloning and purification of proteins: gateway vectors for protein purification by self-cleaving tags.

We have combined Invitrogen's Gateway cloning technology with self-cleaving purification tags to generate a new system for rapid production of recombinant protein products. To accomplish this, we engineered our previously reported DeltaI-CM cleaving intein to include a Gateway cloning recognition sequence, and demonstrated that the resulting Gateway-competent intein is unaffected. This intein can therefore be used in several previously reported purification methods, while at the same time being compatible with Gateway cloning.

Engineered systems for detection and discovery of nuclear hormone-like compounds.

Biomolecular engineering has many applications in the identification of potentially therapeutic compounds. An important class of these compounds is those that bind and modulate the activity of the human nuclear hormone receptors (NHRs). NHRs are typically made up of clearly defined domains with known function, including one that mediates ligand recognition and NHR activation.