Mutations in the N-domain of aryl hydrocarbon receptor interacting protein affect interactions with heat shock protein 90β and phosphodiesterase 4A5.

The aryl hydrocarbon receptor interacting protein (AIP) is a cytoplasmic molecular co-chaperone and tumour suppressor that assists in protein stability and complex formation involving the aryl hydrocarbon receptor. Germline mutations in the AIP gene predispose to pituitary tumourigenesis with patients exhibiting an aggressive clinical phenotype. Full length AIP proteins harbouring N-domain mutations (R9Q, R16H, V49 M and K103R) were purified from E.

Substitution of histidine 30 by asparagine in manganese superoxide dismutase alters biophysical properties and supports proliferation in a K562 leukemia cell line.

We have generated a mutant of C. elegans manganese superoxide dismutase at histidine 30 by site-directed mutagenesis. The structure was solved at a resolution of 1.

Electromechanical coupling of the Kv1.1 voltage-gated K channel is fine-tuned by the simplest amino acid residue in the S4-S5 linker.

Investigating the Shaker-related K channel Kv1.1, the dysfunction of which is responsible for episodic ataxia 1 (EA1), at the functional and molecular level provides valuable understandings on normal channel dynamics, structural correlates underlying voltage-gating, and disease-causing mechanisms. Most studies focused on apparently functional amino acid residues composing voltage-gated K channels, neglecting the simplest ones.

A Single Mutation is Sufficient to Modify the Metal Selectivity and Specificity of a Eukaryotic Manganese Superoxide Dismutase to Encompass Iron.

We have generated a site-directed mutant of the manganese superoxide dismutase SOD-3 of C.elegans (MnSOD-3) which modifies the metal specificity of the enzyme. While wild-type MnSOD-3 functions with manganese in the active site (3600 U mg of protein) it has little or no activity when iron is incorporated.

A channelopathy mutation in the voltage-sensor discloses contributions of a conserved phenylalanine to gating properties of Kv1.1 channels and ataxia.

Channelopathy mutations prove informative on disease causing mechanisms and channel gating dynamics. We have identified a novel heterozygous mutation in the KCNA1 gene of a young proband displaying typical signs and symptoms of Episodic Ataxia type 1 (EA1). This mutation is in the S4 helix of the voltage-sensing domain and results in the substitution of the highly conserved phenylalanine 303 by valine (p.

miRNA Influences in NRF2 Pathway Interactions within Cancer Models.

The NRF2 transcription factor (nuclear factor-erythroid 2 p45-related factor 2) has been identified as a key molecular player in orchestrating adaptive cellular interactions following a wide spectrum of cellular stress conditions that could be either extracellular or intracellular. Dysregulation of the NRF2 system is implicated in various disease states, including inflammatory conditions. The NRF2 transcription factor is also known to permit cross talk with several other essential cellular signaling pathways.

The structure of the Caenorhabditis elegans manganese superoxide dismutase MnSOD-3-azide complex.

C. elegans MnSOD-3 has been implicated in the longevity pathway and its mechanism of catalysis is relevant to the aging process and carcinogenesis. The structures of MnSOD-3 provide unique crystallographic evidence of a dynamic region of the tetrameric interface (residues 41-54).

Determination of metal content in superoxide dismutase enzymes by capillary electrophoresis†.

Superoxide dismutases are antioxidant scavenger enzymes that contain a metal cofactor (copper, zinc, iron, and manganese) in their active site. Metal content measurement is one of the essential steps to characterize enzyme biological activity. We have developed a capillary electrophoretic protocol for the determination of the metal content in superoxide dismutase enzymes.

Interactions in the native state of monellin, which play a protective role against aggregation.

A series of recent studies have provided initial evidence about the role of specific intra-molecular interactions in maintaining proteins in their soluble state and in protecting them from aggregation. Here we show that the amino acid sequence of the protein monellin contains two aggregation-prone regions that are prevented from initiating aggregation by multiple non-covalent interactions that favor their burial within the folded state of the protein. By investigating the behavior of single-chain monellin and a series of five of its mutational variants using a variety of biochemical, biophysical and computational techniques, we found that weakening of the non-covalent interaction that stabilizes the native state of the protein leads to an enhanced aggregation propensity.

Purification, crystallization and X-ray structures of the two manganese superoxide dismutases from Caenorhabditis elegans.

Caenorhabditis elegans expresses two manganese superoxide dismutase enzymes (MnSOD-2 and MnSOD-3) that are targeted to the mitochondrion. MnSOD-2 is constitutively expressed, while synthesis of MnSOD-3 is inducible. The structures of these two mononuclear metalloenzymes have been determined to 1.

Novel polymorphisms influencing transcription of the human CHRM2 gene in airway smooth muscle.

Muscarinic receptors are a functionally important family of G-protein-coupled receptors. Using a combination of rapid amplification of 5' cDNA ends and reporter gene assays, we characterized the 5' untranslated region of the CHRM2 gene as expressed in human airway smooth muscle (HASM) cells. A splice site is present 46 bp upstream from the ATG start codon.

Thermostability of manganese- and iron-superoxide dismutases from Escherichia coli is determined by the characteristic position of a glutamine residue.

The structurally homologous mononuclear iron and manganese superoxide dismutases (FeSOD and MnSOD, respectively) contain a highly conserved glutamine residue in the active site which projects toward the active-site metal centre and participates in an extensive hydrogen bonding network. The position of this residue is different for each SOD isoenzyme (Q69 in FeSOD and Q146 in MnSOD of Escherichia coli). Although site-directed mutant enzymes lacking this glutamine residue (FeSOD[Q69G] and MnSOD[Q146A]) demonstrated a higher degree of selectivity for their respective metal, they showed little or no activity compared with wild types.