Read by QxMD icon Read


Anna J Komor, Andrew J Jasniewski, Lawrence Que, John D Lipscomb
Covering: up to 2017The participation of non-heme dinuclear iron cluster-containing monooxygenases in natural product biosynthetic pathways has been recognized only recently. At present, two families have been discovered. The archetypal member of the first family, CmlA, catalyzes β-hydroxylation of l-p-aminophenylalanine (l-PAPA) covalently linked to the nonribosomal peptide synthetase (NRPS) CmlP, thereby effecting the first step in the biosynthesis of chloramphenicol by Streptomyces venezuelae. CmlA houses the diiron cluster in a metallo-β-lactamase protein fold instead of the 4-helix bundle fold of nearly every other diiron monooxygenase...
March 19, 2018: Natural Product Reports
Breann L Brown, Julia R Kardon, Robert T Sauer, Tania A Baker
5-Aminolevulinic acid synthase (ALAS) catalyzes the first step in heme biosynthesis. We present the crystal structure of a eukaryotic ALAS from Saccharomyces cerevisiae. In this homodimeric structure, one ALAS subunit contains covalently bound cofactor, pyridoxal 5'-phosphate (PLP), whereas the second is PLP free. Comparison between the subunits reveals PLP-coupled reordering of the active site and of additional regions to achieve the active conformation of the enzyme. The eukaryotic C-terminal extension, a region altered in multiple human disease alleles, wraps around the dimer and contacts active-site-proximal residues...
March 5, 2018: Structure
Xiao-Li Xie, Jie-Tao He, Zheng-Tao Wang, Huan-Qin Xiao, Wen-Tao Zhou, Si-Hao Du, Ye Xue, Qi Wang
Methamphetamine (METH) is a widely abused psychostimulant. Lactulose is a non-absorbable sugar, which effectively decreases METH-induced neurotoxicity in rat. However, the exact mechanisms need further investigation. In this study, 5-week-old male Sprague Dawley rats received METH (15 mg/kg, 8 intraperitoneal injections, 12-hour interval) or saline and received lactulose (5.3 g/kg, oral gavage, 12-hour interval) or vehicle 2 days prior to the METH administration. Compared to the control group, in the METH alone group, cytoplasmic vacuolar degeneration in hepatocytes, higher levels of alanine transaminase, aspartate transaminase and ammonia, overproduction of reactive oxygen species (ROS) and increase of superoxide dismutase activity in the blood were observed...
March 14, 2018: Toxicology Letters
Reza Yekta, Gholamreza Dehghan, Samaneh Rashtbari, Rahim Ghadari, Ali Akbar Moosavi-Movahedi
Farnesiferol C (FC) is a natural sesquiterpene coumarin, which includes a widely range of biological activities. In this work, effects of FC on the structure and catalytic function of bovine liver catalase (BLC) was assessed by various spectroscopic and theoretical methods. Kinetic studies showed that FC has a remarkable inhibitory activity on BLC via mixed-type inhibition. The IC50 value as the inhibitory strength of FC was evaluated 1.5 μM. Fluorescence spectroscopy, synchronous fluorescence, CD spectroscopy and UV-vis absorption studies revealed conformational changes in the tertiary and secondary structure of BLC as well as the position of the heme group in the presence of different concentrations of FC...
March 14, 2018: International Journal of Biological Macromolecules
Cláudia S Nóbrega, Bart Devreese, Sofia R Pauleta
The trihemic bacterial cytochrome c peroxidase from Escherichia coli, YhjA, is a membrane-anchored protein with a C-terminal domain homologous to the classical bacterial peroxidases and an additional N-terminal (NT) heme binding domain. Recombinant YhjA is a 50 kDa monomer in solution with three c-type hemes covalently bound. Here is reported the first biochemical and spectroscopic characterization of YhjA and of the NT domain demonstrating that NT heme is His63/Met125 coordinated. The reduction potentials of P (active site), NT and E hemes were established to be - 170 mV, + 133 mV and + 210 mV, respectively, at pH 7...
March 14, 2018: Biochimica et Biophysica Acta
Wei Jiang, Yue Pan, Jiebing Yang, Yong Liu, Yan Yang, Jun Tang, Quanshun Li
Atom transfer radical polymerization (ATRP) has been considered to be an efficient strategy for constructing functional macromolecules owing to its simple operation and versatile monomers, and thus it is of great significance to develop ideal catalysts with higher activity and perfect reusability. We constructed a peroxidase mimic through the grafting of heme onto metal-organic frameworks UiO-66-NH2 (ZrMOF), namely Heme-ZrMOF. After the systematic characterization of structure, the composite Heme-ZrMOF was demonstrated to possess high peroxidase activity using 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) and 3,3',5,5'-tetramethylbenzidine as substrates...
March 9, 2018: Journal of Colloid and Interface Science
S Chevolleau, M-H Noguer-Meireles, I Jouanin, N Naud, F Pierre, F Gueraud, L Debrauwer
Red or processed meat rich diets have been shown to be associated with an elevated risk of colorectal cancer (CRC). One major hypothesis involves dietary heme iron which induces lipid peroxidation. The quantification of the resulting reactive aldehydes (e.g. HNE and HHE) in the colon lumen is therefore of great concern since these compounds are known for their cytotoxic and genotoxic properties. UHPLC-ESI-MS/MS method has been developed and validated for HNE and HHE quantification in rat faeces. Samples were derivatised using a brominated reagent (BBHA) in presence of pre-synthesized deuterated internal standards (HNE-d11/HHE-d5), extracted by solid phase extraction, and then analysed by LC-positive ESI-MS/MS (MRM) on a TSQ Vantage mass spectrometer...
March 2, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Vincent Normant, Thierry Mourer, Simon Labbe
In the fission yeast Schizosaccharomyces pombe , acquisition of exogenous heme is largely mediated by the cell membrane-associated Shu1. Here, we report that Str3, a member of the major facilitator superfamily of transporters promotes cellular heme import. Using a strain that cannot synthesize heme de novo ( hem1Δ ) and lacks Shu1, we found that the heme-dependent growth deficit of this strain is rescued by hemin supplementation in the presence of Str3. Microscopic analyses of a hem1Δ shu1Δ str3Δ mutant strain in the presence of the heme analog zinc mesoporphyrin IX (ZnMP) revealed that ZnMP fails to accumulate within the mutant cells...
March 16, 2018: Journal of Biological Chemistry
Judith Stiefelmaier, Benjamin Ledermann, Michael Sorg, Angela Banek, Doris Geib, Roland Ulber, Nicole Frankenberg-Dinkel
Phycoerythrobilin (PEB) is an open-chain tetrapyrrole derived from heme and plays an important role as light-harvesting pigment in the phycobiliproteins of cyanobacteria and red algae. Furthermore, PEB can also function as an antioxidant with potential use as a natural acid stable food colorant. PEB is not commercially available and large, pure quantities can only be obtained by laborious methanolysis of red algae followed by liquid chromatography. Here we describe an improved method for high yield production and purification of PEB in Escherichia coli via heterologous expression where the two required enzymes heme oxygenase and PEB synthase subsequently convert the substrate heme provided by the host cell...
March 13, 2018: Journal of Biotechnology
Paween Mahinthichaichan, Robert B Gennis, Emad Tajkhorshid
Cytochrome aa3 is the terminal respiratory enzyme of all eukaryotes and many bacteria and archaea, reducing O2 to water and harnessing the free energy from the reaction to generate the transmembrane electrochemical potential. The diffusion of O2 to the heme-copper catalytic site, which is buried deep inside the enzyme, is the initiation step of the reaction chemistry. Our previous molecular dynamics (MD) study with cytochrome ba3 , a homologous enzyme of cytochrome aa3 in Thermus thermophilus, demonstrated that O2 diffuses from the lipid bilayer to its reduction site through a 25-Å long tunnel inferred by Xe-binding sites detected by X-ray crystallography$ ...
March 16, 2018: Biochemistry
Nicolas S Merle, Anne Grunenwald, Marie-Lucile Figueres, Sophie Chauvet, Marie Daugan, Samantha Knockaert, Tania Robe-Rybkine, Remi Noe, Olivia May, Marie Frimat, Nathan Brinkman, Thomas Gentinetta, Sylvia Miescher, Pascal Houillier, Veronique Legros, Florence Gonnet, Olivier P Blanc-Brude, Marion Rabant, Regis Daniel, Jordan D Dimitrov, Lubka T Roumenina
Intravascular erythrocyte destruction, accompanied by the release of pro-oxidative and pro-inflammatory components hemoglobin and heme, is a common event in the pathogenesis of numerous diseases with heterogeneous etiology and clinical features. A frequent adverse effect related to massive hemolysis is the renal injury and inflammation. Nevertheless, it is still unclear whether heme--a danger-associated molecular pattern--and ligand for TLR4 or upstream hemolysis-derived products are responsible for these effects...
2018: Frontiers in Immunology
Rasa Tamosiuniene, Olga Manouvakhova, Paul Mesange, Toshie Saito, Jin Qian, Mrinmoy Sanyal, Yu-Chun Lin, Linh P Nguyen, Amir Luria, Allen B Tu, Joshua M Sante, Marlene Rabinovitch, Desmond J Fitzgerald, Brian B Graham, Aida Habtezion, Norbert F Voelkel, Laure Aurelian, Mark R Nicolls
<u>Rationale:</u> Pulmonary arterial hypertension (PH) is a life-threatening condition associated with immune dysregulation and abnormal regulatory T cell (Treg) activity, but it is currently unknown whether and how abnormal Treg function differentially affects males and females. <u>Objective:</u> To evaluate whether and how Treg-deficiency differentially affects male and female rats in experimental PH. <u>Methods and Results:</u> Male and female athymic rnu/rnu rats, lacking Tregs, were treated with the vascular endothelial growth factor receptor-2 (VEGFR2) inhibitor SU5416 or chronic hypoxia and evaluated for PH; some animals underwent Treg immune reconstitution (IR) before SU5416 administration...
March 15, 2018: Circulation Research
Jin Yang, Yang Liu, Hongjie Liu, Heming Zheng, Xiaofeng Li, Lin Zhu, Zhe Wang
OBJECTIVE: The study aimed to explore the effects of maternal iodine status and thyroid diseases on adverse pregnancy outcomes. METHODS: A prospective study was conducted on 2347 pregnant women, who provided 2347 urinary samples tested for iodine, 1082 serum samples tested for thyroid function, and 2347 questionnaires about demographic information. Their pregnancy outcomes were recorded and compared between different urinary iodine concentration (UIC) and thyroid function groups...
May 2018: Journal of Trace Elements in Medicine and Biology
Hui Zhong, Hidenori Wake, Keyue Liu, Yuan Gao, Kiyoshi Teshigawara, Masakiyo Sakaguchi, Shuji Mori, Masahiro Nishibori
The apoptotic process of erythrocytes is known as eryptosis, and is characterized by phosphatidylserine (PS) expression on the outer membrane. PS-positive erythrocytes are increased in sepsis, and PS is believed to facilitate coagulation of erythrocytes and activate macrophages. However, the relationship between eryptosis and abnormal coagulation in sepsis is still not fully understood. Histidine-rich glycoprotein (HRG) inhibits immunothrombus formation by regulating neutrophils and vascular endothelial cells...
November 24, 2017: Journal of Pharmacological Sciences
Li Chen, Nathchar Naowarojna, Heng Song, Shu Wang, Jianyun Wang, Zixin Deng, Changming Zhao, Pinghua Liu
Ovothiol is a histidine thiol derivative. The biosynthesis of ovothiol involves an extremely efficient trans-sulfuration strategy. The non-heme iron enzyme OvoA catalyzed oxidative coupling be-tween cysteine and histidine is one of the key steps. Besides catalyzing the oxidative coupling between cysteine and histidine, OvoA also catalyzes the oxi-dation of cysteine to cysteine sulfinic acid (cysteine dioxygenase activity). Thus far, very little mecha-nistic information is available for OvoA-catalysis. In this report, we measured the kinetic isotope effect (KIE) in OvoA-catalysis using the isotopically sensitive branching method...
March 15, 2018: Journal of the American Chemical Society
Yuko Arita, Michael Kirk, Neha Gupta, Ramkumar Menon, Darios Getahun, Morgan R Peltier
OBJECTIVE: Tributyltin (TBT) is a persistent pollutant but its effects on placental function are poorly understood as are its possible interactions with infection. We hypothesized that TBT alters the production of sex hormones and biomarkers for inflammation and neurodevelopment in an infection-dependent manner. METHODS: Placental explant cultures were treated with 0-5000 nM TBT in the presence and absence of Escherichia coli. A conditioned medium was harvested and concentrations of steroids (progesterone, P4; testosterone, T and estradiol, E2) as well as biomarkers of inflammation [interleukin (IL)-1β (IL-1β), tumor necrosis factor (TNF-α), IL-10, IL-6, soluble glycoprotein 130 (sgp-130) and heme oxygenase-1 (HO-1)], oxidative stress [8-iso-prostaglandin (8-IsoP)] and neurodevelopment [brain-derived neurotrophic factor (BDNF)] were quantified...
March 15, 2018: Journal of Perinatal Medicine
Luhong He, Jairav Xolo Desai, Jinxin Gao, Laurie B Hazeltine, Zhirui Lian, John N Calley, Christopher C Frye
Oxidation of monoclonal antibodies (mAb) is a common chemical modification with potential impact on a therapeutic protein's activity and immunogenicity. In a previous study, it was found that tryptophan oxidation (Trp-ox) levels of two mAb produced in Chinese hamster ovary (CHO) cells were significantly lowered by modifying cell culture medium/feed. In this study, transcriptome analysis by RNA-Seq was applied to further elucidate the underlying mechanism of those changes in lowering the Trp-ox levels. Cell samples from the 5L fed-batch conditions were harvested and subjected to RNA-Seq analysis...
March 15, 2018: Biotechnology Journal
Wen Zhang, Jun-Ke Song, Rong Yan, Li Li, Zhi-Yong Xiao, Wen-Xia Zhou, Zhen-Zhong Wang, Wei Xiao, Guan-Hua Du
Diterpene ginkgolides meglumine injection (DGMI) is a therapeutic extract of Ginkgo biloba L, which has been used for the treatment of cerebral ischemic stroke in China. Ginkgolides A, B and C are the main components of DGMI. This study was designed to investigate the neuroprotective effects of DGMI components against ischemic stroke in vivo and in vitro. Acute cerebral ischemic injury was induced in rats by occlusion of the middle cerebral artery (MCA) for 1.5 h followed by 24 h reperfusion. The rats were treated with DGMI (1, 3 and 10 mg/kg, iv) at the onset of reperfusion and 12 h after reperfusion...
March 15, 2018: Acta Pharmacologica Sinica
Jinyong Lin, Lingdong Shao, Sufang Qiu, Xingwu Huang, Mengmeng Liu, Zuci Zheng, Duo Lin, Yongliang Xu, Zhihua Li, Yao Lin, Rong Chen, Shangyuan Feng
A home-made near-infrared laser tweezers Raman spectroscopy (LTRS) system was applied to detect hemoglobin variation in red blood cells (RBCs) from diabetes without exogenous labeling. Results showed significant spectral differences existed between the diabetic and normal RBCs, including the peaks dominated by protein components (e.g. 1003 cm-1 ) and heme groups (e.g. 753 cm-1 ) in RBCs, and accurate classification results for diabetes detection were obtained by linear discriminant analysis with 100% sensitivity (i...
March 1, 2018: Biomedical Optics Express
Mariusz Z Ratajczak, Daniel Pedziwiatr, Monika Cymer, Magda Kucia, Jolanta Kucharska-Mazur, Jerzy Samochowiec
Evidence has accumulated that the occurrence of psychiatric disorders is related to chronic inflammation. In support of this linkage, changes in the levels of circulating pro-inflammatory cytokines and chemokines in the peripheral blood (PB) of psychiatric patients as well as correlations between chronic inflammatory processes and psychiatric disorders have been described. Furthermore, an inflammatory process known as "sterile inflammation" when initiated directly in brain tissue may trigger the onset of psychoses...
2018: Frontiers in Psychiatry
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"