Inhibition of electron transfer from adrenodoxin to cytochrome P-450scc by chemical modification with pyridoxal 5'-phosphate: identification of adrenodoxin-binding site of cytochrome P-450scc

Biochemistry ◽  
1989 ◽  
Vol 28 (17) ◽  
pp. 6899-6907 ◽  
Author(s):  
Motonari Tsubaki ◽  
Yoshiki Iwamoto ◽  
Atsuo Hiwatashi ◽  
Yoshiyuki Ichikawa
Keyword(s):  
Electron Transfer ◽  
Chemical Modification ◽  
Binding Site

A new versatile peroxidase from Pleurotus

2001 ◽  
Vol 29 (2) ◽  
pp. 116-122 ◽  
Author(s):  
F. J. Ruiz-Dueñas ◽  
S. Camarero ◽  
M. Pérez-Boada ◽  
M. J. Martínez ◽  
A. T. Martínez
Keyword(s):  
Electron Transfer ◽  
Chemical Modification ◽  
Binding Site ◽  
Lignin Peroxidase ◽  
Manganese Peroxidase ◽  
Veratryl Alcohol ◽  
Substrate Oxidation ◽  
Molecular Models ◽  
Electron Transfer Pathway ◽  
High Affinity

Lignin peroxidase (LiP) and manganese peroxidase (MnP) have been investigated in Phanero-chaete chrysosporium. A third ligninolytic peroxidase has been described in Pleurotus and Bjerkandera. Two of these versatile peroxidases (VPs) have been cloned, sequenced and characterized. They have high affinity for Mn2+, hydro-quinones and dyes, and also oxidize veratryl alcohol, dimethoxybenzene and lignin dimers. The deduced sequences show higher identity with Ph. chrysosporium LiP than MnP, but the molecular models obtained include a Mn2+-binding site. Concerning aromatic substrate oxidation, Pl. eryngii VP shows a putative long-range electron transfer pathway from an exposed trytophan to haem. Mutagenesis and chemical modification of this tryptophan and the acidic residues forming the Mn2+-binding site confirmed their role in catalysis. The existence of several substrate oxidation sites is supported further by biochemical evidence. Residue conservation in other fungal peroxidases is discussed.

scholarly journals The nature of the binding site for aromatic compounds in glycogen phosphorylase b

1975 ◽  
Vol 147 (2) ◽  
pp. 369-371 ◽  
Author(s):  
G Soman ◽  
G Philip
Keyword(s):  
Chemical Modification ◽  
Binding Site ◽  
Aromatic Compounds ◽  
Glycogen Phosphorylase ◽  
Relative Effectiveness ◽  
Rabbit Muscle ◽  
Substituent Constant ◽  
Chemically Modified ◽  
Glycogen Phosphorylase B ◽  
Hydrophobic Nature

The inhibition of rabbit muscle glycogen phosphorylase b (1,4-alpha-D-glucan--orthophosphate alpha-glucosyltransferase, EC 2.4.1.1) by aromatic compounds was examined with 15 compounds. The relative effectiveness of the inhibitors correlated well with increasing substituent constant, pi, indicating the hydrophobic nature of the binding site. The inhibition was not affected by the ionic-strength variation of the assay mixtures. The results predict that the course of chemical modification of this enzyme and the properties of the derivatives depend on the nature of the reagent and on the incorporated groups. Many of the dissimilar and sometimes contradictory results reported for chemical-modification studies and for chemically modified phosphorylase b are explained by the findings presented in the paper.

Molecular Modelling of the Interaction of Cyanoacrylate Inhibitors with Photosystem II Part 2. The Effect of Stereochemistry of Inhibitor Binding

1993 ◽  
Vol 48 (9-10) ◽  
pp. 782-787 ◽  
Author(s):  
Simon P. Mackay ◽  
Patrick J. O’Malley
Keyword(s):  
Electron Transfer ◽  
Photosystem Ii ◽  
Binding Site ◽  
Energy Minimization ◽  
Electrostatic Interactions ◽  
D1 Protein ◽  
Spatial Arrangement ◽  
Inhibitor Binding ◽  
Protein Residues ◽  
Quinone Binding

Abstract The 2-cyanoacrylate inhibitors are a potent class of herbicides which block electron transfer in photosystem II. The spatial arrangement of different functional groups are an important factor in determining activity and a number of derivatives have been used as stereospecific probes of the secondary quinone binding site. More than one region of stereoselectivity in the binding site has been identified which influences the interaction with specific groups of the inhibitor. We have studied the interaction of various stereoisomers of the cyanoacrylates with the binding site in the D1 protein (residues Leu 210 to Val 280) by determining the nonbonded intermolecular energies between the modelled structures calculated by van der Waals and electrostatic interactions after energy minimization of the combined structures to reduce inter and intramolecular strain and have found that the results reflect the experimentally determined data

scholarly journals Electron transfer activity through the quinone-binding site of complex II (succinate: Quinone reductase)

2010 ◽  
Vol 1797 ◽  
pp. 111
Author(s):  
Gary Cecchini ◽  
Elena Maklashina ◽  
Sujata S. Shinde ◽  
Robert F. Anderson ◽  
Russ Hille
Keyword(s):  
Electron Transfer ◽  
Binding Site ◽  
Quinone Reductase ◽  
Complex Ii ◽  
Transfer Activity ◽  
Quinone Binding

scholarly journals Chemical modification studies on a lectin from Saccharomyces cerevisiae (baker's yeast)

1987 ◽  
Vol 244 (3) ◽  
pp. 579-584 ◽  
Author(s):  
M Kundu ◽  
J Basu ◽  
A Ghosh ◽  
P Chakrabarti
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Chemical Modification ◽  
Binding Site ◽  
Structural Changes ◽  
Thiol Groups ◽  
Lectin Activity ◽  
Partial Protection ◽  
Sugar Binding ◽  
Arginine Residues ◽  
Glycine Ethyl Ester

The effect of chemical modification on a galactose-specific lectin isolated from a fatty acid auxotroph of Saccharomyces cerevisiae was investigated in order to identify the type of amino acids involved in its agglutinating activity. Modification of 50 free amino groups with succinic anhydride or citraconic anhydride led to an almost complete loss of activity. This could not be protected by the inhibitory sugar methyl alpha-D-galactopyranoside. Treatment with N-bromosuccinimide and N-acetylimidazole, for the modification of tryptophan and tyrosine residues, did not affect lectin activity. Modification of carboxy groups with glycine ethyl ester greatly affected lectin activity, although sugars afford partial protection. Modification of four thiol groups with N-ethylmaleimide was accompanied by a loss of 85% of the agglutinating activity, and two thiol groups were found to be present at the sugar-binding site of the lectin. Modification of 18 arginine residues with cyclohexane-1,2-dione and 26 histidine residues with ethoxyformic anhydride led to a loss of lectin activity. However, in these cases, modification was not protected by the abovementioned inhibitory sugar, suggesting the absence of these groups at the sugar-binding site. In all the cases, immunodiffusion studies with modified lectin showed no gross structural changes which could disrupt antigenic sites of the lectin.

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