Role of the Amide Carbonyl Groups in the Nitrile Hydratase Active Site for Nitrile Coordination Using Co(III) Complex with N2S3-type Ligand

2015 ◽  
Vol 44 (6) ◽  
pp. 761-763 ◽  
Author(s):  
Takuma Yano ◽  
Tomohiro Ikeda ◽  
Tomonori Shibayama ◽  
Tomohiko Inomata ◽  
Yasuhiro Funahashi ◽  
...  
Keyword(s):  
Active Site ◽  
Nitrile Hydratase ◽  
Carbonyl Groups ◽  
Amide Carbonyl

scholarly journals Analyzing the catalytic role of active site residues in the Fe-type nitrile hydratase from Comamonas testosteroni Ni1

2015 ◽  
Vol 20 (5) ◽  
pp. 885-894 ◽  
Author(s):  
Salette Martinez ◽  
Rui Wu ◽  
Karoline Krzywda ◽  
Veronika Opalka ◽  
Hei Chan ◽  
...  
Keyword(s):  
Active Site ◽  
Nitrile Hydratase ◽  
Comamonas Testosteroni ◽  
Active Site Residues ◽  
Catalytic Role

scholarly journals Key Role of Alkanoic Acids on the Spectral Properties, Activity, and Active-Site Stability of Iron-Containing Nitrile Hydratase fromBrevibacteriumR312

1996 ◽  
Vol 240 (1) ◽  
pp. 239-244 ◽  
Author(s):  
Marie-Aude Kopf ◽  
Didier Bonnet ◽  
Isabella Artaud ◽  
Dominique Pétré ◽  
Daniel Mansuy
Keyword(s):  
Active Site ◽  
Spectral Properties ◽  
Nitrile Hydratase ◽  
Alkanoic Acids

Exploring the Role of the Central Carbide of the Nitrogenase Active-Site FeMo-cofactor through Targeted 13C Labeling and ENDOR Spectroscopy

2021 ◽  
Author(s):  
Ana Pérez-González ◽  
Zhi-Yong Yang ◽  
Dmitriy A. Lukoyanov ◽  
Dennis R. Dean ◽  
Lance C. Seefeldt ◽  
...  
Keyword(s):  
Active Site ◽  
13C Labeling ◽  
Endor Spectroscopy ◽  
Femo Cofactor

scholarly journals Investigation of the active site of oligosaccharyltransferase from pig liver using synthetic tripeptides as tools

1995 ◽  
Vol 312 (3) ◽  
pp. 979-985 ◽  
Author(s):  
E Bause ◽  
W Breuer ◽  
S Peters
Keyword(s):  
Hydroxy Group ◽  
Active Site ◽  
Catalytic Mechanism ◽  
Endoplasmic Reticulum Membrane ◽  
Hydrogen Binding ◽  
Ph Optimum ◽  
Pig Liver ◽  
Acceptor Activity ◽  
Amide Carbonyl ◽  
Amide Carbonyl Group

Oligosaccharyltransferase (OST), an integral component of the endoplasmic-reticulum membrane, catalyses the transfer of dolichyl diphosphate-linked oligosaccharides to specific asparagine residues forming part of the Asn-Xaa-Thr/Ser sequence. We have studied the binding and catalytic properties of the enzyme from pig liver using peptide analogues derived from the acceptor peptide N-benzoyl-Asn-Gly-Thr-NHCH3 by replacing either asparagine or threonine with amino acids differing in size, stereochemistry, polarity and ionic properties. Acceptor studies showed that analogues of asparagine and threonine with bulkier side chains impaired recognition by OST. Reduction of the beta-amide carbonyl group of asparagine yielded a derivative that, although not glycosylated, was strongly inhibitory (50% inhibition at approximately 140 microM). This inhibition may be due to ion-pair formation involving the NH3+ group and a negatively charged base at the active site. Hydroxylation of asparagine at the beta-C position increased Km and decreased Vmax, indicating an effect on both binding and catalysis. The threo configuration at the beta-C atom of the hydroxyamino acid was essential for substrate binding. A peptide derivative obtained by replacement of the threonine beta-hydroxy group with an NH2 group was found to display acceptor activity. This shows that the primary amine is able to mimic the hydroxy group during transglycosylation. The pH optimum with this derivative is shifted by approximately 1 pH unit towards the basic region, indicating that the neutral NH2 group is the reactive species. The various data are discussed in terms of the catalytic mechanism of OST, particular emphasis being placed on the role of threonine/serine in increasing the nucleophilicity of the beta-amide of asparagine through hydrogen-binding.

scholarly journals The Role of Active Site Arginines of Sorghum NADP-Malate Dehydrogenase in Thioredoxin-dependent Activation and Activity

2000 ◽  
Vol 275 (46) ◽  
pp. 35792-35798 ◽  
Author(s):  
Isabelle Schepens ◽  
Eric Ruelland ◽  
Myroslawa Miginiac-Maslow ◽  
Pierre Le Maréchal ◽  
Paulette Decottignies
Keyword(s):  
Malate Dehydrogenase ◽  
Active Site
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