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Journal of Molecular Biology Nov 2008The evolutionary pressures that shaped the specificity and catalytic efficiency of enzymes can only be speculated. While directed evolution experiments show that new...
The evolutionary pressures that shaped the specificity and catalytic efficiency of enzymes can only be speculated. While directed evolution experiments show that new functions can be acquired under positive selection with few mutations, the role of negative selection in eliminating undesired activities and achieving high specificity remains unclear. Here we examine intermediates along the 'lineage' from a naturally occurring C12-C20 fatty acid hydroxylase (P450BM3) to a laboratory-evolved P450 propane monooxygenase (P450PMO) having 20 heme domain substitutions compared to P450BM3. Biochemical, crystallographic, and computational analyses show that a minimal perturbation of the P450BM3 fold and substrate-binding pocket accompanies a significant broadening of enzyme substrate range and the emergence of propane activity. In contrast, refinement of the enzyme catalytic efficiency for propane oxidation (approximately 9000-fold increase in kcat/Km) involves profound reshaping and partitioning of the substrate access pathway. Remodeling of the substrate-recognition mechanisms ultimately results in remarkable narrowing of the substrate profile around propane and enables the acquisition of a basal iodomethane dehalogenase activity as yet unknown in natural alkane monooxygenases. A highly destabilizing L188P substitution in a region of the enzyme that undergoes a large conformational change during catalysis plays an important role in adaptation to the gaseous alkane. This work demonstrates that positive selection alone is sufficient to completely respecialize the cytochrome P450 for function on a nonnative substrate.
Topics: Amino Acid Substitution; Chromatography, Gas; Crystallography, X-Ray; Cytochrome P-450 Enzyme System; Evolution, Molecular; Hydrolases; Kinetics; Models, Molecular; Oxidation-Reduction; Propane; Protein Structure, Secondary; Substrate Specificity; Terpenes
PubMed: 18619466
DOI: 10.1016/j.jmb.2008.06.060 -
BioMed Research International 2018The aim of this study was to compare the antibacterial activity of two compounds derived from , PTS (propyl-propane-thiosulfinate), and PTSO...
Antibacterial Activity of Propyl-Propane-Thiosulfinate and Propyl-Propane-Thiosulfonate Derived from spp. against Gram-Negative and Gram-Positive Multidrug-Resistant Bacteria Isolated from Human Samples.
BACKGROUND
The aim of this study was to compare the antibacterial activity of two compounds derived from , PTS (propyl-propane-thiosulfinate), and PTSO (propyl-propane-thiosulfonate), with that of other antibiotics commonly used against bacteria isolated from humans.
MATERIALS AND METHODS
A total of 212 gram-negative bacilli and 267 gram-positive cocci isolated from human clinical samples and resistant to at least one group of antibiotics were selected. In order to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) to various antibiotics as well as PTS and PTSO, all isolates underwent broth microdilution assay.
RESULTS
PTS showed moderate activity against with MIC (and MBC) and MIC (and MBC) values of 256-512 mg/L, while PTSO showed greater activity with MIC and MIC values of 64-128 mg/L and MBC and MBC values of 128-512 mg/L. These data show the bactericidal activity of both compounds and indicate that PTSO was more active than PTS against this group of bacteria. Both compounds showed lower activity against (MIC = 1024 mg/L, MIC = 2048 mg/L, MBC = 2048 mg/L, and MBC = 2048 mg/L, for PTS; MIC = 512 mg/L, MIC = 1024 mg/L, MBC = 512 mg/L, and MBC = 2048 mg/L, for PTSO) compared to those obtained in others nonfermenting gram-negative bacilli (MIC = 128 mg/L, MIC = 512 mg/L, MBC = 128 mg/L, and MBC = 512 mg/L, for PTS; MIC = 64 mg/L, MIC = 256 mg/L, MBC = 64 mg/L, and MBC = 256 mg/L, for PTSO) and also indicate the bactericidal activity of both compounds against these groups of bacteria. Finally, the activity against , , and was higher than that observed against enterobacteria, especially in the case of PTSO (MIC = 8 mg/L, MIC = 8 mg/L, MBC = 32 mg/L, and MBC = 64 mg/L, in ; MIC = 4 mg/L, MIC = 8 mg/L, MBC = 8 mg/L, and MBC = 16 mg/L, in and ).
CONCLUSION
PTS and PTSO have a significant broad spectrum antibacterial activity against multiresistant bacteria isolated from human clinical samples. Preliminary results in present work provide basic and useful information for development and potential use of these compounds in the treatment of human infections.
Topics: Allium; Anti-Bacterial Agents; Bacteria; Bacterial Infections; Drug Resistance, Multiple, Bacterial; Humans; Microbial Sensitivity Tests; Plant Extracts; Propane; Thiosulfonic Acids
PubMed: 30310819
DOI: 10.1155/2018/7861207 -
Environmental Health Perspectives Feb 1997
Topics: Animals; Body Weight; Dose-Response Relationship, Drug; Epididymis; Female; Fertility; Kidney; Litter Size; Liver; Male; Mice; Organ Size; Ovary; Pregnancy; Propane; Reproduction; Solvents; Sperm Count
PubMed: 9114362
DOI: No ID Found -
International Journal of Molecular... Aug 2023Skin photoaging due to ultraviolet B (UVB) exposure generates reactive oxygen species (ROS) that increase matrix metalloproteinase (MMP). Chlorin e6-photodynamic therapy...
Skin photoaging due to ultraviolet B (UVB) exposure generates reactive oxygen species (ROS) that increase matrix metalloproteinase (MMP). Chlorin e6-photodynamic therapy (Ce6-PDT), in addition to being the first-line treatment for malignancies, has been shown to lessen skin photoaging, while curcumin is well known for reducing the deleterious effects of ROS. In the current study, PDT with three novel Ce6-curcumin derivatives, a combination of Ce6 and curcumin with various linkers, including propane-1,3-diamine for Ce6-propane-curcumin; hexane-1,6-diamine for Ce6-hexane-curcumin; and 3,3'-((oxybis(ethane-2,1-diyl))bis(oxy))bis(propan-1-amine) for Ce6-dipolyethylene glycol (diPEG)-curcumin, were studied for regulation of UVB-induced photoaging on human skin fibroblast (Hs68) and mouse embryonic fibroblast (BALB/c 3T3) cells. We assessed the antiphotoaging effects of Ce6-curcumin derivatives on cell viability, antioxidant activity, the mechanism of matrix metalloproteinase-1 and 2 (MMP-2) expression, and collagen synthesis in UVB-irradiated in vitro models. All three Ce6-curcumin derivatives were found to be non-phototoxic in the neutral red uptake phototoxicity test. We found that Ce6-hexane-curcumin-PDT and Ce6-propane-curcumin-associated PDT exhibited less cytotoxicity in Hs68 and BALB/c 3T3 fibroblast cell lines compared to Ce6-diPEG-curcumin-PDT. Ce6-diPEG-curcumin and Ce6-propane-curcumin-associated PDT showed superior antioxidant activity in Hs68 cell lines. Further, in UVB-irradiated in vitro models, the Ce6-diPEG-curcumin-PDT greatly attenuated the expression levels of MMP-1 and MMP-2 by blocking mitogen-activated protein kinases (MAPKs), activator protein 1 (AP-1), and tumor necrosis factor-α (NF-κB) signaling. Moreover, Ce6-diPEG-curcumin effectively inhibited inflammatory molecules, such as cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression, while accelerating collagen synthesis. These results demonstrate that Ce6-diPEG-curcumin may be a potential therapy for treating skin photoaging.
Topics: Animals; Mice; Humans; Curcumin; Hexanes; Matrix Metalloproteinase 2; Antioxidants; Propane; Reactive Oxygen Species; Fibroblasts; Dermatitis, Phototoxic; Glycols; Photochemotherapy; Collagen
PubMed: 37686273
DOI: 10.3390/ijms241713468 -
Antimicrobial Agents and Chemotherapy Oct 2022Clofazimine [N,5-bis(4-chlorophenyl)-3-[(propane-2-yl)rimino]-3,5-dihydrophenazin-2-amine] is an antimycobacterial agent used as a second-line antituberculosis (anti-TB)...
Clofazimine [N,5-bis(4-chlorophenyl)-3-[(propane-2-yl)rimino]-3,5-dihydrophenazin-2-amine] is an antimycobacterial agent used as a second-line antituberculosis (anti-TB) drug. Nonetheless, little information is known about the metabolic routes of clofazimine, and the enzymes involved in metabolism. This study aimed to characterize the metabolic pathways and enzymes responsible for the metabolism of clofazimine in human liver microsomes. Eight metabolites, including four oxidative metabolites, three glucuronide conjugates, and one sulfate conjugate were identified, and their structures were deduced based on tandem mass spectrometry (MS/MS) spectra. Hydroxylated clofazimine and hydrated clofazimine was generated even in the absence of the NADPH generating system presumably via a nonenzymatic pathway. Hydrolytic-dehalogenated clofazimine was catalyzed mainly by CYP1A2 whereas hydrolytic-deaminated clofazimine was formed by CYP3A4/A5. In case of glucuronide conjugates, UGT1A1, UGT1A3, and UGT1A9 showed catalytic activity toward hydroxylated and hydrated clofazimine glucuronide whereas hydrolytic-deaminated clofazimine glucuronide was catalyzed by UGT1A4, UGT1A9, UGT1A3, and UGT2B4. Our results suggested that CYP1A2 and CYP3A are involved in the formation of oxidative metabolites while UGT1A1, 1A3, 1A4, 1A9, and 2B4 are involved in the formation of glucuronide conjugates of oxidative metabolites of clofazimine.
Topics: Humans; Microsomes, Liver; Glucuronides; Cytochrome P-450 CYP1A2; Cytochrome P-450 CYP3A; Clofazimine; Tandem Mass Spectrometry; NADP; Propane; Glucuronosyltransferase; Sulfates; Amines; Anti-Bacterial Agents; Liver
PubMed: 36190267
DOI: 10.1128/aac.00565-22 -
Acta Biomaterialia Apr 2019Cholesterol esterase-like (CE) activity from saliva and esterase from cariogenic bacteria hydrolyze ester linkages of dental methacrylate resins. Collagenolytic, matrix...
Cholesterol esterase-like (CE) activity from saliva and esterase from cariogenic bacteria hydrolyze ester linkages of dental methacrylate resins. Collagenolytic, matrix metalloproteinase-like (MMP) activities from dentin and bacteria degrade collagen in demineralized tooth dentin. Human neutrophils in the oral cavity contain factors that are hypothesized to have CE and MMP activities that could contribute to the degradation of methacrylate resins and dentinal collagen. OBJECTIVES: To measure the CE and MMP activities from human neutrophils and their ability to degrade dental methacrylate resin composite and dentinal collagen. Neutrophils' CE and MMP activities were measured using nitrophenyl-esters or fluorimetric MMP substrates, respectively. Neutrophils' degradation of resin composite and dentinal collagen was quantified by measuring release of a universal 2,2-Bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (bisGMA)-derived resin composite degradation byproduct, bishydroxy-propoxy-phenyl-propane (bisHPPP), or a collagen degradation by-product, hydroxyproline, respectively using ultra performance liquid chromatography/mass spectrometry. Neutrophils' CE activity increased the release of bisHPPP from bisGMA monomer compared to control after 24 and 48 h (p < 0.05). Neutrophils degraded polymerized resin composite and produced higher amounts of bisHPPP than buffer after 48 h of incubation (p < 0.05). Neutrophils show generic MMP, gelatinase, MMP-2 and MMP-9, and collagenase, MMP-1 and MMP-8 activities that were stable or increased over the first 24 h (p < 0.05). Neutrophils degraded demineralized dentin more than buffer-only groups, indicated by higher amounts of hydroxyproline (p < 0.05). The ability of neutrophils to degrade both dental resin composite and tooth dentin, suggest neutrophil's potential role in root caries, and in recurrent carries by accelerating the degradation of resin-dentin interfaces, and compromising the longevity of the restoration. STATEMENT OF SIGNIFICANCE: Neutrophils are part of the innate immune system and are constantly entering the oral cavity through the gingival sulcus, in direct contact with the tooth, restoration, restoration-tooth margins and pathogenic bacteria. The current study is the first to characterize and quantify degradative activities from neutrophils toward methacrylate resin and demineralized dentin, the two main components of the restoration-tooth interface, suggesting that this interface could be negatively influenced by neutrophils, potentially contributing to increase in caries formation and progression, and premature restoration failure. This study provides a significant finding to the biomaterials and oral health fields by identifying a potential weakness in current restorative procedures and materials used to manage gingival proximal and cervical gingival or sub-gingival carious lesions.
Topics: Acrylic Resins; Cell Survival; Collagen; Composite Resins; Dentin; Humans; Hydroxyproline; Leukocyte Elastase; Matrix Metalloproteinases; Methacrylates; Neutrophils; Polyurethanes; Propane; Proteolysis; Sterol Esterase; Tooth
PubMed: 30807874
DOI: 10.1016/j.actbio.2019.02.033 -
Scientific Reports Jun 2019The anti-angiogenic agent, diamino propane tetraiodothyroacetic acid (DAT), is a thyro-integrin (integrin αvβ3) antagonist anticancer agent that works via genetic and...
The anti-angiogenic agent, diamino propane tetraiodothyroacetic acid (DAT), is a thyro-integrin (integrin αvβ3) antagonist anticancer agent that works via genetic and nongenetic actions. Tetraiodothyroacetic acid (tetrac) and DAT as thyroid hormone derivatives influence gene expression after they transport across cellular membranes. To restrict the action of DAT to the integrin αvβ3 receptors on the cell surface, we used DAT-conjugated PLGA nanoparticles (NDAT) in an active targeting mode to bind to these receptors. Preparation and characterization of NDAT is described, and both in vitro and in vivo experiments were done to compare DAT to NDAT. Intracellular uptake and distribution of DAT and NDAT in U87 glioblastoma cells were evaluated using confocal microscopy and showed that DAT reached the nucleus, but NDAT was restricted from the nucleus. Pharmacokinetic studies using LC-MS/MS analysis in male C57BL/6 mice showed that administration of NDAT improved the area under the drug concentration curve AUC by 4-fold at a dose of 3 mg/kg when compared with DAT, and C of NDAT (4363 ng/mL) was 8-fold greater than that of DAT (548 ng/mL). Biodistribution studies in the mice showed that the concentrations of NDAT were higher than DAT/Cremophor EL micelles in heart, lung, liver, spleen, and kidney. In another mouse model using female NCr nude homozygous mice with U87 xenografts, tumor growth was significantly decreased at doses of 1 and 3 mg/kg of NDAT. In the chick chorioallantoic membrane (CAM) assay used to measure angiogenesis, DAT (500 ng/CAM) resulted in 48% inhibition of angiogenesis levels. In comparison, NDAT at low dose (50 ng/CAM) showed 45% inhibition of angiogenesis levels. Our investigation of NDAT bridges the study of polymeric nanoparticles and anti-angiogenic agents and offers new insight for the rational design of anti-angiogenic agents.
Topics: Animals; Biocompatible Materials; Cell Line, Tumor; Chickens; Chorioallantoic Membrane; Female; Glioblastoma; Humans; Male; Mice, Inbred C57BL; Mice, Nude; Nanoparticles; Neovascularization, Pathologic; Polymers; Propane; Thyroxine; Tissue Distribution; Xenograft Model Antitumor Assays
PubMed: 31227723
DOI: 10.1038/s41598-019-44979-6 -
Scientific Reports Mar 2022Bacteriocins and reuterin are promising antimicrobials for application in food, veterinary, and medical sectors. In the light of their high potential for application in...
Bacteriocins and reuterin are promising antimicrobials for application in food, veterinary, and medical sectors. In the light of their high potential for application in hand sanitizer, we investigated the skin toxicity of reuterin, microcin J25, pediocin PA-1, bactofencin A, and nisin Z in vitro using neutral red and LDH release assays on NHEK cells. We determined their skin sensitization potential using the human cell line activation test (h-CLAT). Their skin irritation potential was measured on human epidermal model EpiDerm™. We showed that the viability and membrane integrity of NHEK cells remained unaltered after exposure to bacteriocins and reuterin at concentrations up to 400 µg/mL and 80 mg/mL, respectively. Furthermore, microcin J25 and reuterin showed no skin sensitization at concentrations up to 100 µg/mL and 40 mg/mL, respectively, while pediocin PA-1, bactofencin A, and nisin Z caused sensitization at concentrations higher than 100 µg/mL. Tissue viability was unaffected in presence of bacteriocins and reuterin at concentrations up to 200 µg/mL and 40 mg/mL, respectively, which was confirmed by measuring cytokine IL-1α and IL-8 levels and by histological analysis. In conclusion, the current study provides scientific evidence that some bacteriocins and reuterin, could be safely applied topically as sanitizers at recommended concentrations.
Topics: Bacteriocins; Glyceraldehyde; Humans; Propane
PubMed: 35301365
DOI: 10.1038/s41598-022-08441-4 -
Science Advances May 2024Gas and propane stoves emit nitrogen dioxide (NO) pollution indoors, but the exposures of different U.S. demographic groups are unknown. We estimate NO exposure and...
Gas and propane stoves emit nitrogen dioxide (NO) pollution indoors, but the exposures of different U.S. demographic groups are unknown. We estimate NO exposure and health consequences using emissions and concentration measurements from >100 homes, a room-specific indoor air quality model, epidemiological risk parameters, and statistical sampling of housing characteristics and occupant behavior. Gas and propane stoves increase long-term NO exposure 4.0 parts per billion volume on average across the United States, 75% of the World Health Organization's exposure guideline. This increased exposure likely causes ~50,000 cases of current pediatric asthma from long-term NO exposure alone. Short-term NO exposure from typical gas stove use frequently exceeds both World Health Organization and U.S. Environmental Protection Agency benchmarks. People living in residences <800 ft in size incur four times more long-term NO exposure than people in residences >3000 ft in size; American Indian/Alaska Native and Black and Hispanic/Latino households incur 60 and 20% more NO exposure, respectively, than the national average.
Topics: Nitrogen Dioxide; Humans; United States; Air Pollution, Indoor; Propane; Environmental Exposure; Housing; Cooking; Air Pollutants
PubMed: 38701214
DOI: 10.1126/sciadv.adm8680 -
Report on Carcinogens : Carcinogen... 2011
Topics: Animals; Carcinogenicity Tests; Carcinogens, Environmental; Environmental Exposure; Government Regulation; Guidelines as Topic; Humans; Molecular Structure; Nitroparaffins; Occupational Exposure; Propane; Rats
PubMed: 21860502
DOI: No ID Found