Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.

| S-EPMC2531291 | biostudies-literature

Homo sapiens

Project description:Identification of Unique Therapeutic Targets in Esophageal Squamous Cell Carcinoma

| PRJNA140407 | ENA

Homo sapiens whole blood.

Project description:RNA extracted at 240min. Samples are rRNA depleted. Expression measurement of Homo sapiens genes.

2019-07-31 | GSE114179 | GEO

Homo sapiens

Project description:Identification of novel long non-coding RNAs in prostate cancers

| PRJNA256097 | ENA

Global gene expression profiles in ovarian cancer linked to Lynch syndrome

Project description:Heredity is a major cause of ovarian cancer. Lynch syndrome is associated with 10-12% risk of ovarian cancer, diagnosis at young age and a predilection for endometrioid and clear cell tumors. Global gene expression profiling applied to 25 Lynch syndrome-associated and 42 sporadic ovarian cancers revealed 335 differentially expressed genes and involvement of the mTOR and the MAPK/ERK pathways. The clear cell tumors had distinct expression profiles with upregulation of HER2 and apoptosis signaling pathways. The distinct expression profiles provide clues relevant for hereditary tumorigenesis and may be relevant for therapeutic strategies and refined diagnostics in ovarian cancer linked to Lynch syndrome. Ovarian cancers linked to Lynch syndrome (n=25) were compared to a matched series of sporadic ovarian cancers (n=42), selected from a population-based consecutive series in which hereditary was excluded based on family history, normal MMR protein staining and lack of mutations in BRCA1 and BRCA2.

2013-10-14 | E-GEOD-37394 | biostudies-arrayexpress

Homo sapiens

Project description:Prospective Procurement of Solid Tumor Tissue to Identify Novel Therapeutic Targets

| PRJNA298376 | ENA