scholarly journals MetW regulates the enzymatic activity of MetX in Pseudomonas

2021 ◽  
Vol 85 (2) ◽  
pp. 351-358
Author(s):  
Fumihito Hasebe
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Amino Acid ◽  
Enzymatic Activity ◽  
Binding Site ◽  
Biosynthetic Pathway ◽  
Feedback Inhibition ◽  
Regulatory Protein ◽  
Inhibitory Effect ◽  
Canonical Amino Acid ◽  
The Relationship

ABSTRACT Methionine is a canonical amino acid. The protein MetX is a homoserine O-acyltransferase utilized in the methionine biosynthetic pathway. The metW gene is found adjacent to the metX gene in some bacteria, but its functions are unclear. In this study, I focused on the function of MetW and MetX from Pseudomonas aeruginosa (PaMetW and PaMetX). I demonstrated that PaMetW interacted with and activated the homoserine O-succinyltransferase (HST) activity of PaMetX. Furthermore, I elucidated that the HST activity of PaMetX in complex with PaMetW was inhibited by the addition of S-adenosyl-l-homocysteine (SAH), although PaMetX alone showed no feedback inhibition. Since PaMetW possesses a glycine-rich sequence annotated as a SAM/SAH binding site, I also investigated the relationship between this glycine-rich sequence and the inhibition caused by SAH. I revealed that alanine mutation of PaMetW Gly24 reduced the inhibitory effect of SAH. These results suggest that MetW is a regulatory protein of MetX.

scholarly journals Amino Acid-Mediated Induction of the Basic Amino Acid-Specific Outer Membrane Porin OprD from Pseudomonas aeruginosa

1999 ◽  
Vol 181 (17) ◽  
pp. 5426-5432 ◽  
Author(s):  
Martina M. Ochs ◽  
Chung-Dar Lu ◽  
Robert E. W. Hancock ◽  
Ahmed T. Abdelal
Keyword(s):  
Amino Acids ◽  
Pseudomonas Aeruginosa ◽  
Amino Acid ◽  
Regulatory Protein ◽  
Basic Amino Acid ◽  
Sole Source ◽  
Activation Mechanism ◽  
Beta Lactam ◽  
Mobility Shift ◽  
Carbon And Nitrogen

ABSTRACT Pseudomonas aeruginosa can utilize arginine and other amino acids as both carbon and nitrogen sources. Earlier studies have shown that the specific porin OprD facilitates the diffusion of basic amino acids as well as the structurally analogous beta-lactam antibiotic imipenem. The studies reported here showed that the expression of OprD was strongly induced when arginine, histidine, glutamate, or alanine served as the sole source of carbon. The addition of succinate exerted a negative effect on induction ofoprD, likely due to catabolite repression. The arginine-mediated induction was dependent on the regulatory protein ArgR, and binding of purified ArgR to its operator upstream of theoprD gene was demonstrated by gel mobility shift and DNase assays. The expression of OprD induced by glutamate as the carbon source, however, was independent of ArgR, indicating the presence of more than a single activation mechanism. In addition, it was observed that the levels of OprD responded strongly to glutamate and alanine as the sole sources of nitrogen. Thus, that the expression ofoprD is linked to both carbon and nitrogen metabolism ofPseudomonas aeruginosa.

L-SERINE DEHYDRATASE (DEAMINASE) OF PSYCHROPHILES AND MESOPHILES FROM POLAR AND TEMPERATE HABITATS

1967 ◽  
Vol 13 (10) ◽  
pp. 1333-1342 ◽  
Author(s):  
James T. Staley ◽  
William L. Boyd
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Enzymatic Activity ◽  
Growth Temperature ◽  
Enzymic Activity ◽  
Direct Role ◽  
Natural Plant ◽  
Serine Dehydratase ◽  
The Relationship ◽  
Dehydratase Activity

Escherichia coli and Pseudomonas aeruginosa were grown at several temperatures ranging from 0° to 37 °C and assayed at each temperature for L-serine dehydratase activity. The relationship between enzymatic activity and growth temperature is quite different for the mesophile and psychrophile. In addition, the stimulatory effect of natural plant lecithin upon serine deamination was different for each organism, suggesting that there is either a difference in permeability or that this substance has a more direct role in enzymic activity. Also included are data confirming the results of other workers.

scholarly journals Mechanism and site of action of big dynorphin on ASIC1a

2019 ◽  
Author(s):  
C.B. Borg ◽  
N. Braun ◽  
S.A. Heusser ◽  
Y. Bay ◽  
D. Weis ◽  
...  
Keyword(s):  
Amino Acids ◽  
Ischemic Stroke ◽  
Amino Acid ◽  
Binding Site ◽  
Neuronal Death ◽  
Electrostatic Interactions ◽  
Rational Design ◽  
Site Of Action ◽  
Canonical Amino Acid

AbstractAcid-sensing ion channels (ASICs) are proton-gated cation channels that contribute to neurotransmission, as well as initiation of pain and neuronal death following ischemic stroke. As such, there is a great interest in understanding the in vivo regulation of ASICs, especially by endogenous neuropeptides that potently modulate ASICs. The most potent endogenous ASIC modulator known to date is the opioid neuropeptide big dynorphin (BigDyn). BigDyn is upregulated in chronic pain and increases ASIC-mediated neuronal death during acidosis. Understanding the mechanism and site of action of BigDyn on ASICs could thus enable the rational design of compounds potentially useful in the treatment of pain and ischemic stroke. To this end, we employ a combination of electrophysiology, voltage-clamp fluorometry, synthetic BigDyn analogs and non-canonical amino acid-mediated photocrosslinking. We demonstrate that BigDyn binding results in an ASIC1a closed resting conformation that is distinct from open and desensitized states induced by protons. Using alanine-substituted BigDyn analogs, we find that the BigDyn modulation of ASIC1a is mediated through electrostatic interactions of basic amino acids in the BigDyn N-terminus. Furthermore, neutralizing acidic amino acids in the ASIC1a extracellular domain reduces BigDyn effects, suggesting a binding site at the acidic pocket. This is confirmed by photocrosslinking using the non-canonical amino acid azido-phenylalanine. Overall, our data define the mechanism of how BigDyn modulates ASIC1a, identify the acidic pocket as the binding site for BigDyn and thus highlight this cavity as an important site for the development of ASIC-targeting therapeutics.Significance StatementNeuropeptides such as big dynorphin (BigDyn) play important roles in the slow modulation of fast neurotransmission, which is mediated by membrane-embedded receptors. In fact, BigDyn is the most potent known endogenous modulator of one such receptor, the acid-sensing ion channel (ASIC), but the mode of action remains unknown. In this work, we employ a broad array of technologies to unravel the details of where big dynorphin binds to ASIC and how it modulates its activity. As both BigDyn and ASIC are implicated in pain pathways, this work might pave the way towards future analgesics.

scholarly journals Evaluation of the Antibacterial and Investigation of the Molecular Docking of New Derivatives of 1, 3, 4-Oxadiazole as Inhibitors of Quorum Sensing System in the Human Pathogen Pseudomonas Aeruginosa

2021 ◽  
Vol 8 (1) ◽  
pp. 27-33
Author(s):  
Sepideh Ghameshlouei ◽  
Nakisa Zarrabi Ahrabi ◽  
Ali Souldozi ◽  
Yasin SarveAhrabi
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Molecular Docking ◽  
Quorum Sensing ◽  
Regulatory Protein ◽  
Inhibitory Effect ◽  
Chemical Structures ◽  
Sensing System ◽  
Wide Range ◽  
Quorum Sensing System ◽  
Derivatives Of

Background: Oxadiazoles are a group of anti-inflammatory compounds that have a wide range of activity due to their higher efficacy. Pseudomonas aeruginosa is an opportunistic pathogen and a major pathogen of nosocomial infections. This study aimed to evaluate the antibacterial and investigation of the molecular docking of new derivatives of 1, 3, 4-oxadiazole against P. aeruginosa, in vitro & in silico. Materials and Methods: Four new derivatives were synthesized and added to our previous synthetic derivatives of 1, 3, 4-oxadiazole. The antibacterial activity of all derivatives was measured based on three standard species of P. aeruginosa using inhibition zone (IZ) and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods. Then, employing the computational design of the drug by the molecular docking method, the inhibitory effect of synthetic compounds on the LasR regulatory protein of P. aeruginosa quorum sensing system was investigated, which plays an important role in regulating the expression of pathogenic genes in bacteria. Results: The chemical structures of new compounds were characterized by IR spectra and 1H-NMR. A variety of inhibitory effects were observed by the synthesized compounds – compound 4d and 4g, in particular. Also, the inhibitory effect of these two compounds on the LasR regulatory protein under the control of the quorum sensing system in P. aeruginosa was demonstrated by molecular docking. Conclusions: The results of this study showed that the two compounds containing the functional group of naphthalene and fluorophenyl have a significant effect on the inhibition of P. aeruginosa, as well as on the LasR protein of this bacterium.

scholarly journals Cloning, sequencing and analysis of the structural gene and regulatory region of the Pseudomonas aeruginosa chromosomal ampCβ-lactamase

1990 ◽  
Vol 272 (3) ◽  
pp. 627-631 ◽  
Author(s):  
J M Lodge ◽  
S D Minchin ◽  
L J V Piddock ◽  
S J W Busby
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Binding Site ◽  
Regulatory Protein ◽  
Regulatory Region ◽  
Open Reading Frame ◽  
Beta Lactamase ◽  
Chromosomal Gene ◽  
Reading Frame ◽  
Beta Lactamases ◽  
Lactamase Gene

The chromosomal gene from Pseudomonas aeruginosa encoding beta-lactamase has been cloned, and the sequence determined and compared with corresponding sequences of beta-lactamases from members of the enterobacteriaceae. Upstream of the beta-lactamase gene is an open reading frame which we postulate encodes a regulatory protein, AmpR. We identified a helix-turn-helix region in AmpR and a putative AmpR-binding site.

scholarly journals Structural Basis for the Regulation of N-Acetylglutamate Kinase by PII in Arabidopsis thaliana

2007 ◽  
Vol 282 (49) ◽  
pp. 35733-35740 ◽  
Author(s):  
Yutaka Mizuno ◽  
Greg B. G. Moorhead ◽  
Kenneth K.-S. Ng
Keyword(s):  
Arabidopsis Thaliana ◽  
Feedback Inhibition ◽  
Regulatory Protein ◽  
Enzyme Regulation ◽  
Inhibitory Effect ◽  
Structural Basis ◽  
Atp Binding Site ◽  
Domains Of Life ◽  
Substrate Binding Sites ◽  
Acetylglutamate Kinase

PII is a highly conserved regulatory protein found in organisms across the three domains of life. In cyanobacteria and plants, PII relieves the feedback inhibition of the rate-limiting step in arginine biosynthesis catalyzed by N-acetylglutamate kinase (NAGK). To understand the molecular structural basis of enzyme regulation by PII, we have determined a 2.5-Å resolution crystal structure of a complex formed between two homotrimers of PII and a single hexamer of NAGK from Arabidopsis thaliana bound to the metabolites N-acetylglutamate, ADP, ATP, and arginine. In PII, the T-loop and Trp22 at the start of the α1-helix, which are both adjacent to the ATP-binding site of PII, contact two β-strands as well as the ends of two central helices (αE and αG) in NAGK, the opposing ends of which form major portions of the ATP and N-acetylglutamate substrate-binding sites. The binding of Mg2+·ATP to PII stabilizes a conformation of the T-loop that favors interactions with both open and closed conformations of NAGK. Interactions between PII and NAGK appear to limit the degree of opening and closing of the active-site cleft in opposition to a domain-separating inhibitory effect exerted by arginine, thus explaining the stimulatory effect of PII on the kinetics of arginine-inhibited NAGK.

Molecular characterization ofGluconobacter oxydans recAgene and its inhibitory effect on the function of the host wild-typerecAgene

1998 ◽  
Vol 44 (2) ◽  
pp. 149-156 ◽  
Author(s):  
Yu-Tien Liu ◽  
Der-Chiang Chao ◽  
Fan Lee ◽  
Chia-Geun Chen ◽  
Dar-Der Ji
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Amino Acid ◽  
Nucleotide Sequence ◽  
Amino Acid Sequence ◽  
Reca Protein ◽  
Gluconobacter Oxydans ◽  
Inhibitory Effect ◽  
Reca Gene ◽  
Wild Type ◽  
E Coli

A DNA fragment containing the recA gene of Gluconobacter oxydans was isolated and further characterized for its nucleotide sequence and ability to functionally complement various recA mutations. When expressed in an Escherichia coli recA host, the G. oxydans recA protein could efficiently function in homologous recombination and DNA damage repair. The recA gene's nucleotide sequence analysis revealed a protein of 344 amino acids with a molecular mass of 38 kDa. We observed an E. coli-like LexA repressor-binding site in the G. oxydans recA gene promoter region, suggesting that a LexA-like mediated response system may exist in G. oxydans. The expression of G. oxydans recA in E. coli RR1, a recA+strain, surprisingly caused a remarkable reduction of the host wild-type recA gene function, whereas the expression of both Serratia marcescens recA and Pseudomonas aeruginosa recA gene caused only a slight inhibitory effect on function of the host wild-typerecA gene product. Compared with the E. coli RecA protein, the identity of the amino acid sequence of G. oxydans RecA protein is much lower than those RecA proteins of both S. marcescens and Pseudomonas aeruginosa. This result suggests that the expression of another wild-type RecA could interfere with host wild-type recA gene's function, and the extent of such an interference is possibly correlated to the identity of the amino acid sequence between the two classes of RecA protein.Key words: Gluconobacter oxydans, recA gene, recombination, SOS function, interference.

Efficient photo-oxidation of phenol and photo-inactivation of bacteria by cationic tetrakis(trimethylanilinium)porphyrins

2015 ◽  
Vol 15 (5) ◽  
pp. 1099-1105 ◽  
Author(s):  
Fatemeh Fayyaz ◽  
Rahmatollah Rahimi ◽  
Mehdi Rassa ◽  
Ali Maleki
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Metal Ion ◽  
Inhibitory Effect ◽  
Gram Negative ◽  
Photo Oxidation ◽  
Gram Positive Bacteria ◽  
Buffer Solutions ◽  
Oxidation Of Phenol ◽  
The Relationship ◽  
Inactivation Of Bacteria

Photo-oxidation of phenol in aqueous alkaline and neutral buffer solutions by irradiation with visible light in the presence of 5,10,15,20-tetrakis(4-N,N,N-trimethylanilinium)porphyrin (TAPP) and its zinc metal ion (ZnTAPP) photo-sensitizers is described. The inhibitory effect of these molecules on the growth of Gram-positive bacteria Bacillus subtilis and Bacillus strophaeus and the Gram-negative strain Pseudomonas aeruginosa has also been examined. Furthermore, to determine the relationship between inhibition and attachment, the degree of binding of these photo-sensitizers to these bacteria was determined. The results show that TAPP is more effective than ZnTAPP in the photo-oxidation of phenol and photo-inactivation of the bacteria. In addition, the degree of binding of TAPP to these bacteria was more than that of ZnTAPP.

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