Allosteric inhibition of hypoxia inducible factor-2 with small molecules.

Hypoxia inducible factors (HIFs) are heterodimeric transcription factors induced in many cancers where they frequently promote the expression of protumorigenic pathways. Though transcription factors are typically considered 'undruggable', the PAS-B domain of the HIF-2α subunit contains a large cavity within its hydrophobic core that offers a unique foothold for small-molecule regulation. Here we identify artificial ligands that bind within this pocket and characterize the resulting structural and functional changes caused by binding.

An E3 ligase possessing an iron-responsive hemerythrin domain is a regulator of iron homeostasis.

Cellular iron homeostasis is maintained by the coordinate posttranscriptional regulation of genes responsible for iron uptake, release, use, and storage through the actions of the iron regulatory proteins IRP1 and IRP2. However, the manner in which iron levels are sensed to affect IRP2 activity is poorly understood. We found that an E3 ubiquitin ligase complex containing the FBXL5 protein targets IRP2 for proteasomal degradation.

On the mechanism of quinol oxidation at the QP site in the cytochrome bc1 complex: studied using mutants lacking cytochrome bL or bH.

To elucidate the mechanism of bifurcated oxidation of quinol in the cytochrome bc1 complex, Rhodobacter sphaeroides mutants, H198N and H111N, lacking heme bL and heme bH, respectively, were constructed and characterized. Purified mutant complexes have the same subunit composition as that of the wild-type complex, but have only 9-11% of the electron transfer activity, which is sensitive to stigmatellin or myxothiazol. The Em values for hemes bL and bH in the H111N and H198N complexes are -95 and -35 mV, respectively.

Domain conformational switch of the iron-sulfur protein in cytochrome bc1 complex is induced by the electron transfer from cytochrome bL to bH.

Intensive biochemical, biophysical and structural studies of the cytochrome (cyt) bc(1) complex in the past have led to the formulation of the "protonmotive Q-cycle" mechanism for electron and proton transfer in this vitally important complex. The key step of this mechanism is the separation of electrons during the oxidation of a substrate quinol at the Q(P) site with both electrons transferred simultaneously to ISP and cyt b(L) when the extrinsic domain of ISP (ISP-ED) is located at the b-position. Pre-steady state fast kinetic analysis of bc(1) demonstrates that the reduced ISP-ED moves to the c(1)-position to reduce cyt c(1) only after the reduced cyt b(L) is oxidized by cyt b(H).

Formation of engineered intersubunit disulfide bond in cytochrome bc1 complex disrupts electron transfer activity in the complex.

Protein domain movement of the Rieske iron-sulfur protein has been speculated to play an essential role in the bifurcated oxidation of ubiquinol catalyzed by the cytochrome bc1 complex. To better understand the electron transfer mechanism of the bifurcated ubiquinol oxidation at Qp site, we fixed the head domain of ISP at the cyt c1 position by creating an intersubunit disulfide bond between two genetically engineered cysteine residues: one at position 141 of ISP and the other at position 180 of the cyt c1 [S141C(ISP)/G180C(cyt c1)]. The formation of a disulfide bond between ISP and cyt c1 in this mutant complex is confirmed by SDS-PAGE and Western blot.

Construction and characterization of a recombinant fowlpox virus containing HIV-1 multi-epitope-p24 chimeric gene in mice.

The epidemic of HIV/AIDS is sweeping across the world. It is of great importance to figure out new ways to curb this disease. Epitope-based vaccine is one of these solutions.

[The advance of tumor development mechanism applying mTR-/- mouse model].

Telomerase is Ribonucleoprotein complex in eukaryocyte, which is composed of telomerase reverse transcriptase(TERT) and telomerase RNA. Telomerase is a special DNA polymerase which can extend the terminal of DNA and maintain the length of telomere. TERT have reverse transcriptase activity.

[Amplification, cloning and sequence analysis of spider dragline silk cDNA].

Spider dragline silk is synthesized in special gland named major ampulate (MA) gland. The MA glands were dissected from the abdomen of the spiders Nephila clavata and the total RNA was extracted by the TRIZOL. The cDNA of dragline silk was amplificated by RT-PCR (reverse transcription polymerase chain reaction), multiplex PCR and cloned.