Modification of Spectroscopic Properties and Catalytic Activity ofEscherichia coliCueO by Mutations of Methionine 510, the Axial Ligand to the Type I Cu

2009 ◽  
Vol 82 (4) ◽  
pp. 504-508 ◽  
Author(s):  
Shinji Kurose ◽  
Kunishige Kataoka ◽  
Naoya Shinohara ◽  
Yuko Miura ◽  
Maiko Tsutsumi ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Spectroscopic Properties ◽  
Axial Ligand ◽  
Type I

Stable Iron Porphyrin Intramolecularly Coordinated by Alcoholate Anion: Synthesis and Evaluation of Axial Ligand Effect of Alcoholate on Spectroscopy and Catalytic Activity

2019 ◽  
Vol 58 (7) ◽  
pp. 4268-4274
Author(s):  
Yoshinori Shirakawa ◽  
Yuuki Yano ◽  
Yuki Niwa ◽  
Kanako Inabe ◽  
Naoki Umezawa ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Axial Ligand ◽  
Iron Porphyrin ◽  
Ligand Effect

scholarly journals The catalytic activity of the endoplasmic reticulum-resident protein microsomal epoxide hydrolase towards carcinogens is retained on inversion of its membrane topology

1996 ◽  
Vol 319 (1) ◽  
pp. 131-136 ◽  
Author(s):  
Thomas FRIEDBERG ◽  
Romy HOLLER ◽  
Bettina LÖLLMANN ◽  
Michael ARAND ◽  
Franz OESCH
Keyword(s):  
Endoplasmic Reticulum ◽  
Catalytic Activity ◽  
Epoxide Hydrolase ◽  
Membrane Topology ◽  
Microsomal Epoxide Hydrolase ◽  
Type I ◽  
Type Ii ◽  
Membrane Orientation ◽  
N Terminus ◽  
Cytochrome P 450

Diol epoxides formed by the sequential action of cytochrome P-450 and the microsomal epoxide hydrolase (mEH) in the endoplasmic reticulum (ER) represent an important class of ultimate carcinogenic metabolites of polycyclic aromatic hydrocarbons. The role of the membrane orientation of cytochrome P-450 and mEH relative to each other in this catalytic cascade is not known. Cytochrome P-450 is known to have a type I topology. According to the algorithm of Hartman, Rapoport and Lodish [(1989) Proc. Natl. Acad. Sci. U.S.A. 86, 5786–5790], which allows the prediction of the membrane topology of proteins, mEH should adopt a type II membrane topology. Experimentally, mEH membrane topology has been disputed. Here we demonstrate that, in contrast with the theoretical prediction, the rat mEH has exclusively a type I membrane topology. Moreover we show that this topology can be inverted without affecting the catalytic activity of mEH. Our conclusions are supported by the observation that two mEH constructs (mEHg1 and mEHg2), containing engineered potential glycosylation sites at two separate locations after the C-terminal site of the membrane anchor, were not glycosylated in fibroblasts. However, changing the net charge at the N-terminus of these engineered mEH proteins by +3 resulted in proteins (++mEHg1 and ++mEHg2) that became glycosylated and consequently had a type II topology. The sensitivity of these glycosylated proteins to endoglycosidase H indicated that, like the native mEH, they are still retained in the ER. The engineered mEH proteins were integrated into membranes as they were resistant to alkaline extraction. Interestingly, an insect mEH with a charge distribution in its N-terminus similar to ++mEHg1 has recently been isolated. This enzyme might well display a type II topology instead of the type I topology of the rat mEH. Importantly, mEHg1, having the natural cytosolic orientation, as well as ++mEHg1, having an artificial luminal orientation, displayed rather similar substrate turnovers for the mutagenic metabolite benzo[a]pyrene 4,5-oxide. To our knowledge this is the first report demonstrating that topological inversion of a protein within the membrane of the ER has only a moderate effect on its enzymic activity, despite differences in folding pathways and redox environments on each side of the membrane. This observation represents an important step in the evaluation of the influence of mEH membrane orientation in the cascade of events leading to the formation of ultimate carcinogenic metabolites, and for studying the general importance of metabolic channelling on the surface of membranes.

Axial ligand effect on the catalytic activity of biomimetic Fe-porphyrin catalyst: An experimental and DFT study

2016 ◽  
Vol 344 ◽  
pp. 768-777 ◽  
Author(s):  
Konstantinos C. Christoforidis ◽  
Dimitrios A. Pantazis ◽  
Luis L. Bonilla ◽  
Eleni Bletsa ◽  
Maria Louloudi ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Axial Ligand ◽  
Dft Study ◽  
Ligand Effect

scholarly journals A co-opted ISG15-USP18 binding mechanism normally reserved for deISGylation controls type I IFN signalling

2021 ◽  
Author(s):  
Andri Vasou ◽  
Katie Nightingale ◽  
Vladimira Cetkovska ◽  
Connor GG Bamford ◽  
Jelena Andrejeva ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Autoinflammatory Disease ◽  
Type I Interferon ◽  
Negative Regulator ◽  
Regulatory Function ◽  
Type I ◽  
Binding Mechanism ◽  
Tight Control ◽  
Non Covalent Interactions ◽  
Covalent Interactions

Type I interferon (IFN) signalling induces the expression of several hundred IFN-stimulated genes that provide an unfavourable environment for viral replication. To prevent an overexuberant response and autoinflammatory disease, IFN signalling requires tight control. One critical regulator is the ubiquitin-like protein ISG15, evidenced by autoinflammatory disease in patients with inherited ISG15 deficiencies. Current models suggest that ISG15 stabilises USP18, a well-established negative regulator of IFN signalling. USP18 also functions as an ISG15-specific peptidase, however its catalytic activity is dispensable for controlling IFN signalling. Here, we show that the ISG15-dependent stabilisation of USP18 is necessary but not sufficient for regulation of IFN signalling and that USP18 requires non-covalent interactions with ISG15 to enhance its regulatory function. Intriguingly, this trait has been acquired through co-option of a binding mechanism normally reserved for deISGylation, identifying an unexpected new function for ISG15.

scholarly journals Dinitrosylmolybdenum Complexes with Anion Ligands Coordinating by Oxygen Atoms. Synthesis, Electronic Structure and Olefin Metathesis Activity of Carboxylato-Dinitrosyl-Molybdenum Complexes

1992 ◽  
Vol 47 (10) ◽  
pp. 1469-1476 ◽  
Author(s):  
Antoni Keller ◽  
Ludmiła Szterenberg
Keyword(s):  
Electronic Structure ◽  
Catalytic Activity ◽  
Excited States ◽  
Olefin Metathesis ◽  
Spectroscopic Properties ◽  
Metathesis Reaction ◽  
Molybdenum Complexes ◽  
H Nmr ◽  
Spectroscopic Investigations ◽  
Oxygen Atoms

The new carboxylato-dinitrosyl-molybdenum complexes of the formula: [Mo(NO)2(O2CMe)2] • MeOH, Na2[Mo(NO)2(O2CMe)4] and Mo(NO)2(O2CPh)2 have been synthesized. Their structure was resolved on the basis of spectroscopic investigations (1H NMR, IR, UV-VIS). Catalytic activity of these complexes in olefin metathesis reaction was also examined.The electronic structure of dinitrosyl-molybdenum complexes with ligands coordinating by oxygen atoms was calculated for the example of the di- and tetra-acetato-dinitrosyl-molybdenum complexes using the Fenske-Hall and INDO methods. To interpret the spectroscopic properties (UV-VIS) within the method of interaction configuration, the electronic structure of the excited states was calculated.

Effects of axial ligand mutation of the type I copper site in bilirubin oxidase on direct electron transfer-type bioelectrocatalytic reduction of dioxygen

2007 ◽  
Vol 601 (1-2) ◽  
pp. 119-124 ◽  
Author(s):  
Yuji Kamitaka ◽  
Seiya Tsujimura ◽  
Kunishige Kataoka ◽  
Takeshi Sakurai ◽  
Tokuji Ikeda ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Direct Electron Transfer ◽  
Axial Ligand ◽  
Type I ◽  
Bilirubin Oxidase ◽  
Copper Site
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