scholarly journals Structural comparison of p-hydroxybenzoate hydroxylase (PobA) from Pseudomonas putida with PobA from other Pseudomonas spp. and other monooxygenases

2019 ◽  
Vol 75 (7) ◽  
pp. 507-514
Author(s):  
John T. Lazar ◽  
Ludmilla Shuvalova ◽  
Monica Rosas-Lemus ◽  
Olga Kiryukhina ◽  
Karla J. F. Satchell ◽  
...  
Keyword(s):  
Pseudomonas Putida ◽  
Binding Sites ◽  
Drug Target ◽  
Tetracycline Resistance ◽  
Hydroxybenzoate Hydroxylase ◽  
Substrate Binding Sites ◽  
Key Residues ◽  
Polypeptide Chains ◽  
Β Sheet ◽  
Fad Binding

The crystal structure is reported of p-hydroxybenzoate hydroxylase (PobA) from Pseudomonas putida, a possible drug target to combat tetracycline resistance, in complex with flavin adenine dinucleotide (FAD). The structure was refined at 2.2 Å resolution with four polypeptide chains in the asymmetric unit. Based on the results of pairwise structure alignments, PobA from P. putida is structurally very similar to PobA from P. fluorescens and from P. aeruginosa. Key residues in the FAD-binding and substrate-binding sites of PobA are highly conserved spatially across the proteins from all three species. Additionally, the structure was compared with two enzymes from the broader class of oxygenases: 2-hydroxybiphenyl 3-monooxygenase (HbpA) from P. nitroreducens and 2-methyl-3-hydroxypyridine-5-carboxylic acid oxygenase (MHPCO) from Mesorhizobium japonicum. Despite having only 14% similarity in their primary sequences, pairwise structure alignments of PobA from P. putida with HbpA from P. nitroreducens and MHPCO from M. japonicum revealed local similarities between these structures. Key secondary-structure elements important for catalysis, such as the βαβ fold, β-sheet wall and α12 helix, are conserved across this expanded class of oxygenases.

scholarly journals Structures and mechanism of the monoamine oxidase family

2011 ◽  
Vol 2 (5) ◽  
pp. 365-377 ◽  
Author(s):  
Helena Gaweska ◽  
Paul F. Fitzpatrick
Keyword(s):  
Monoamine Oxidase ◽  
Binding Sites ◽  
Flavin Adenine Dinucleotide ◽  
Catalytic Reactions ◽  
Secondary Amines ◽  
Binding Domains ◽  
The Family ◽  
Substrate Binding Sites ◽  
Fad Binding ◽  
Methylated Lysine

AbstractMembers of the monoamine oxidase family of flavoproteins catalyze the oxidation of primary and secondary amines, polyamines, amino acids, and methylated lysine side chains in proteins. The enzymes have similar overall structures, with conserved flavin adenine dinucleotide (FAD)-binding domains and varied substrate-binding sites. Multiple mechanisms have been proposed for the catalytic reactions of these enzymes. The present review compares the structures of different members of the family and the various mechanistic proposals.

Crystal structures of the GH6 Orpinomyces sp. Y102 CelC7 enzyme with exo and endo activity and its complex with cellobiose

2019 ◽  
Vol 75 (12) ◽  
pp. 1138-1147
Author(s):  
Hsiao-Chuan Huang ◽  
Liu-Hong Qi ◽  
Yo-Chia Chen ◽  
Li-Chu Tsai
Keyword(s):  
Enzymatic Hydrolysis ◽  
Crystal Structures ◽  
Active Site ◽  
Binding Sites ◽  
Glycoside Hydrolase ◽  
Catalytic Domain ◽  
Glycoside Hydrolase Family ◽  
Substrate Binding Sites ◽  
Key Residues ◽  
Hydrolase Family

The catalytic domain (residues 128–449) of the Orpinomyces sp. Y102 CelC7 enzyme (Orp CelC7) exhibits cellobiohydrolase and cellotriohydrolase activities. Crystal structures of Orp CelC7 and its cellobiose-bound complex have been solved at resolutions of 1.80 and 2.78 Å, respectively. Cellobiose occupies subsites +1 and +2 within the active site of Orp CelC7 and forms hydrogen bonds to two key residues: Asp248 and Asp409. Furthermore, its substrate-binding sites have both tunnel-like and open-cleft conformations, suggesting that the glycoside hydrolase family 6 (GH6) Orp CelC7 enzyme may perform enzymatic hydrolysis in the same way as endoglucanases and cellobiohydrolases. LC-MS/MS analysis revealed cellobiose (major) and cellotriose (minor) to be the respective products of endo and exo activity of the GH6 Orp CelC7.

scholarly journals Identification of Peptide Antagonists to Thioredoxin Glutathione Reductase ofSchistosoma japonicum

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Li-Jun Song ◽  
Jia-Huang Li ◽  
Xu-Ren Yin ◽  
Wei Zhang ◽  
Yi Jin ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Glutathione Reductase ◽  
Binding Sites ◽  
Drug Target ◽  
Promising Candidate ◽  
Phage Display Peptide Library ◽  
Novel Drugs ◽  
Alternative Drug ◽  
Substrate Binding Sites ◽  
Thioredoxin Glutathione Reductase

Schistosomiasis is one of the world’s major public health problems. Praziquantel is currently the only effective drug against schistosomiasis. As resistance of praziquantel has emerged in some endemic areas, development of new antischistosomal agents should be a high priority. In this study, a phage display peptide library was used for screening for peptide antagonists of thioredoxin glutathione reductase ofSchistosoma japonicum(SjTGR), which has been identified as an alternative drug target. Three rounds of panning produced four different fusion phages. ELISA proved that all four phages could bind to SjTGR. One peptide, JIPDys1 (aa, WPHNWWPHFKVK), reduced enzyme activity of SjTGR by more than 50%. 2μM of the synthesized peptide of JIPDys1 inhibited the activity of TrxR, GR, and Grx of SjTGR by 32.5%, 100%, and 100%, respectively. The IC50values of the synthetic peptide JIPDys1 for TrxR, GR, and Grx were 3.67μM, 0.11μM, and 0.97μM, respectively. Based on computer simulation, it appeared that JIPDys1 binds to the substrate binding sites of glutathione reductase (GR) and glutaredoxin (Grx). Our data show that the peptide, JIPDys1 (aa, WPHNWWPHFKVK), is a promising candidate to develop novel drugs againstS. japonicumwhich acts by binding with SjTGR and reduces enzyme activity of SjTGR.

scholarly journals Mapping the Substrate-Binding Sites in the Phosphatidylserine Synthase in Candida albicans

2021 ◽  
Vol 11 ◽  
Author(s):  
Yue Zhou ◽  
Chelsi D. Cassilly ◽  
Todd B. Reynolds
Keyword(s):  
Candida Albicans ◽  
Binding Sites ◽  
Drug Target ◽  
Substrate Binding ◽  
Pathogenic Fungi ◽  
Binding Motif ◽  
Conserved Residues ◽  
Alanine Substitution ◽  
Phosphatidylserine Synthase ◽  
Substrate Binding Sites

The fungal phosphatidylserine (PS) synthase, a membrane protein encoded by the CHO1 gene, is a potential drug target for pathogenic fungi, such as Candida albicans. However, both substrate-binding sites of C. albicans Cho1 have not been characterized. Cho1 has two substrates: cytidyldiphosphate-diacylglycerol (CDP-DAG) and serine. Previous studies identified a conserved CDP-alcohol phosphotransferase (CAPT) binding motif, which is present within Cho1. We tested the CAPT motif for its role in PS synthesis by mutating conserved residues using alanine substitution mutagenesis. PS synthase assays revealed that mutations in all but one conserved amino acid within the CAPT motif resulted in decreased Cho1 function. In contrast, there were no clear motifs in Cho1 for binding serine. Therefore, to identify the serine binding site, PS synthase sequences from three fungi were aligned with sequences of a similar enzyme, phosphatidylinositol (PI) synthase, from the same fungi. This revealed a motif that was unique to PS synthases. Using alanine substitution mutagenesis, we found that some of the residues in this motif are required for Cho1 function. Two alanine substitution mutants, L184A and R189A, exhibited contrasting impacts on PS synthase activity, and were characterized for their Michaelis-Menten kinetics. The L184A mutant displayed enhanced PS synthase activity and showed an increased Vmax. In contrast, R189A showed decreased PS synthase activity and increased Km for serine, suggesting that residue R189 is involved in serine binding. These results help to characterize PS synthase substrate binding, and should direct rational approaches for finding Cho1 inhibitors that may lead to better antifungals.

m-[o-(2-Chloro-5-Fluorosulfonylphenylureido)Phenoxybutoxy]Benzamidine: Affinity Labeling Reagent Which Can Identify Secondary Binding Sites of Coagulation Complement and Fibrinolytic Serine Proteases

1979 ◽  
Author(s):  
D Bing ◽  
D Robison ◽  
J Andrews ◽  
R Laura
Keyword(s):  
Binding Sites ◽  
Serine Proteases ◽  
Enzyme Inhibitor ◽  
Molecular Model ◽  
Factor Xa ◽  
Affinity Labeling ◽  
Catalytic Center ◽  
Inhibitor Complex ◽  
Polypeptide Chains ◽  
Kinetics Of

We have determined that m-[o-(2-chloro-5-fluorosulfonylphenylureido)phenoxybutoxy]benza-midine [mCP(PBA)-F] is an affinity labeling reagent which labels both polypeptide chains of thrombin, factor Xa, complement component CIS and plasmin. As this means it is reacting outside of the catalytic center, we have called this reagent an exo-site affinity labeling reagent. Progressive irreversible inhibition of these enzymes by this reagent is rapid (k1st 2.5-4.6 x 10-3sec-1), the kinetics of inactivation are consistent with inhibition proceding via formation of a specific enzyme-inhibitor complex analogous to a Michaelis-Menton complex (KL - 115-26 μM), and diisopropylfluorophosphate or p-amidino-phenylmethanesulfonyfluoride Prevent labeling by [3H]mCP(PBA)-F. A molecular model of mCP(PBA)-F shows that the reactive SO2F group can be 17 A from the cationic amidine. The data are consistent with the hypothesis that both peptide chains are required for the specific proteolytic activity exhibited by these proteases and that the peptide chain which does not contain the active site serine is close to the catalytic center. (Supported by NIH and AHA grants

Inhibitor Binding Sites in the Protein Tyrosine Phosphatase SHP-2

2020 ◽  
Vol 20 (11) ◽  
pp. 1017-1030
Author(s):  
Haonan Zhang ◽  
Zhengquan Gao ◽  
Chunxiao Meng ◽  
Xiangqian Li ◽  
Dayong Shi
Keyword(s):  
Small Molecule ◽  
Protein Tyrosine Phosphatase ◽  
Binding Sites ◽  
Drug Target ◽  
Tyrosine Phosphatase ◽  
Cancer Drug ◽  
Cellular Activity ◽  
Binding Modes ◽  
Inhibitor Binding ◽  
Protein Tyrosine

Protein tyrosine phosphatase 2 (SHP-2) has long been proposed as a cancer drug target. Several small-molecule compounds with different mechanisms of SHP-2 inhibition have been reported, but none are commercially available. Pool selectivity over protein tyrosine phosphatase 1 (SHP-1) and a lack of cellular activity have hindered the development of selective SHP-2 inhibitors. In this review, we describe the binding modes of existing inhibitors and SHP-2 binding sites, summarize the characteristics of the sites involved in selectivity, and identify the suitable groups for interaction with the binding sites.

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