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https://www.readbyqxmd.com/read/28505894/re-the-prognostic-significance-of-the-early-postoperative-neutrophil-to-lymphocyte-ratio-in-patients-with-urothelial-carcinoma%C3%A2-of%C3%A2-the%C3%A2-bladder-undergoing-radical-cystectomy
#1
https://www.readbyqxmd.com/read/28487403/cluster-assembly-in-nitrogenase
#2
REVIEW
Nathaniel S Sickerman, Lee A Rettberg, Chi Chung Lee, Yilin Hu, Markus W Ribbe
The versatile enzyme system nitrogenase accomplishes the challenging reduction of N2and other substrates through the use of two main metalloclusters. For molybdenum nitrogenase, the catalytic component NifDK contains the [Fe8S7]-core P-cluster and a [MoFe7S9C-homocitrate] cofactor called the M-cluster. These chemically unprecedented metalloclusters play a critical role in the reduction of N2, and both originate from [Fe4S4] clusters produced by the actions of NifS and NifU. Maturation of P-cluster begins with a pair of these [Fe4S4] clusters on NifDK called the P*-cluster...
May 9, 2017: Essays in Biochemistry
https://www.readbyqxmd.com/read/28476884/insights-into-catalysis-of-lysine-tryptophan-bond-in-bacterial-peptides-by-a-spasm-domain-radical-sam-peptide-cyclase
#3
Alhosna Benjdia, Laure Decamps, Alain Guillot, Xavier Kubiak, Pauline Ruffie, Corine Sandstrom, Olivier Berteau
Radical SAM enzymes are emerging as a major superfamily of biological catalysts involved in the biosynthesis of the broad family of bioactive peptides called ribosomally synthesized and post-translationally-modified peptides (RiPPs). These enzymes have been shown to catalyze unconventional reactions such as methyl transfer to electrophilic carbon atoms, sulfur to Cα-atom thioether bonds or carbon-carbon bond formation. Recently, a novel radical SAM enzyme catalyzing the formation of a lysine-tryptophan bond has been identified in Streptococcus thermophilus and a reaction mechanism has been proposed...
May 5, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28455341/lack-of-methylated-hopanoids-renders-the-cyanobacterium-nostoc-punctiforme-sensitive-to-osmotic-and-ph-stress
#4
Tamsyn J Garby, Emily D Matys, Sarah E Ongley, Anya Salih, Anthony W D Larkum, Malcolm R Walter, Roger E Summons, Brett A Neilan
To investigate the function of 2-methylhopanoids in modern cyanobacteria, the hpnP gene coding for the radical SAM methylase protein that acts on the C2 position of hopanoids, was deleted from the filamentous cyanobacterium Nostoc punctiforme ATCC 29133S. The resulting ΔhpnP mutant lacked all 2-methylhopanoids, but was found to produce much higher levels of two bacteriohopanepentol isomers compared to the wild type. Growth rates of ΔhpnP mutant cultures were not significantly different from those of the wild type under standard growth conditions...
April 28, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28451191/construction-of-an-octosyl-acid-backbone-catalyzed-by-a-radical-s-adenosylmethionine-enzyme-and-a-phosphatase-in-the-biosynthesis-of-high-carbon-sugar-nucleoside-antibiotics
#5
Nisha He, Pan Wu, Yongxing Lei, Baofu Xu, Xiaochen Zhu, Gudan Xu, Yaojie Gao, Jianzhao Qi, Zixin Deng, Gongli Tang, Wenqing Chen, Youli Xiao
Unique bicyclic octosyl uronic acid nucleosides include ezomycin, malayamycin, and octosyl acid (OA). They are structurally characterized by OA, an unusual 8-carbon furanosyl nucleoside core proposed to be the precursor to polyoxin and nikkomycin. Despite the well-known bioactivity of these nucleoside antibiotics, the biosynthesis of OA has not been elucidated yet. Here we report the two pivotal enzymatic steps in the polyoxin biosynthetic pathway leading to the identification of OA as a key intermediate. Our data suggest that this intermediate is formed via a free radical reaction catalyzed by the radical S-adenosylmethionine (SAM) enzyme, PolH, and using 3'-enolpyruvyl uridine 5'-monophosphate (3'-EUMP) as a substrate...
January 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28443932/nucleoside-linked-shunt-products-in-the-reaction-catalyzed-by-the-class-c-radical-s-adenosylmethionine-methyltransferase-nosn
#6
Wei Ding, Yujie Wu, Xinjian Ji, Haocheng Qianzhu, Fener Chen, Zixin Deng, Yi Yu, Qi Zhang
NosN is a class C radical S-adenosylmethionine (SAM) methyltransferase (RSMT) involved in the biosynthesis of nosiheptide, a clinically interesting thiopeptide antibiotic produced by Streptomyces actuosus. NosN employs an unprecedented catalytic mechanism, in which SAM is converted to 5'-methylthioadenosine (MTA) as a direct methyl donor. In this study, we report identification of several nucleoside-linked shunt products in the NosN-catalyzed reaction. Comparative analysis of NosN and the class A RSMT RlmN and further density functional theory (DFT) calculations reveal important mechanistic insights into the catalyses of the two types of enzymes, showing that the radical intermediates generated by similar pathways can have very diverse reactivities...
May 4, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28383907/substrate-dependent-cleavage-site-selection-by-unconventional-radical-s-adenosylmethionine-enzymes-in-diphthamide-biosynthesis
#7
Min Dong, Masaki Horitani, Boris Dzikovski, Jack H Freed, Steven E Ealick, Brian M Hoffman, Hening Lin
S-Adenosylmethionine (SAM) has a sulfonium ion with three distinct C-S bonds. Conventional radical SAM enzymes use a [4Fe-4S] cluster to cleave homolytically the C5',adenosine-S bond of SAM to generate a 5'-deoxyadenosyl radical, which catalyzes various downstream chemical reactions. Radical SAM enzymes involved in diphthamide biosynthesis, such as Pyrococcus horikoshii Dph2 (PhDph2) and yeast Dph1-Dph2 instead cleave the Cγ,Met-S bond of methionine to generate a 3-amino-3-carboxylpropyl radical. We here show radical SAM enzymes can be tuned to cleave the third C-S bond to the sulfonium sulfur by changing the structure of SAM...
April 13, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28366513/cost-of-new-technologies-in-prostate-cancer-treatment-systematic-review-of-costs-and-cost-effectiveness-of-robotic-assisted-laparoscopic-prostatectomy-intensity-modulated-radiotherapy-and-proton-beam-therapy
#8
REVIEW
Florian Rudolf Schroeck, Bruce L Jacobs, Sam B Bhayani, Paul L Nguyen, David Penson, Jim Hu
CONTEXT: Some of the high costs of robot-assisted radical prostatectomy (RARP), intensity-modulated radiotherapy (IMRT), and proton beam therapy may be offset by better outcomes or less resource use during the treatment episode. OBJECTIVE: To systematically review the literature to identify the key economic trade-offs implicit in a particular treatment choice for prostate cancer. EVIDENCE ACQUISITION: We systematically reviewed the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement and protocol...
March 30, 2017: European Urology
https://www.readbyqxmd.com/read/28361051/on-the-role-of-additional-4fe-4s-clusters-with-a-free-coordination-site-in-radical-sam-enzymes
#9
REVIEW
Etienne Mulliez, Victor Duarte, Simon Arragain, Marc Fontecave, Mohamed Atta
The canonical CysXXXCysXXCys motif is the hallmark of the Radical-SAM superfamily. This motif is responsible for the ligation of a [4Fe-4S] cluster containing a free coordination site available for SAM binding. The five enzymes MoaA, TYW1, MiaB, RimO and LipA contain in addition a second [4Fe-4S] cluster itself bound to three other cysteines and thus also displaying a potentially free coordination site. This review article summarizes recent important achievements obtained on these five enzymes with the main focus to delineate the role of this additional [4Fe-4S] cluster in catalysis...
2017: Frontiers in Chemistry
https://www.readbyqxmd.com/read/28346939/a-b12-dependent-radical-sam-enzyme-involved-in-oxetanocin-a-biosynthesis
#10
Jennifer Bridwell-Rabb, Aoshu Zhong, He G Sun, Catherine L Drennan, Hung-Wen Liu
Oxetanocin A (OXT-A) is a potent antitumour, antiviral and antibacterial compound. Biosynthesis of OXT-A has been linked to a plasmid-borne Bacillus megaterium gene cluster that contains four genes: oxsA, oxsB, oxrA and oxrB. Here we show that both the oxsA and oxsB genes are required for the production of OXT-A. Biochemical analysis of the encoded proteins, a cobalamin (Cbl)-dependent S-adenosylmethionine (AdoMet) radical enzyme, OxsB, and an HD-domain phosphohydrolase, OxsA, reveals that OXT-A is derived from a 2'-deoxyadenosine phosphate in an OxsB-catalysed ring contraction reaction initiated by hydrogen atom abstraction from C2'...
April 20, 2017: Nature
https://www.readbyqxmd.com/read/28338506/a-preliminary-report-radical-surgery-and-stem-cell-transplantation-for-the-treatment-of-patients-with-pancreatic-cancer
#11
Brigitta Omazic, Burcu Ayoglu, Matthias Löhr, Ralf Segersvärd, Caroline Verbeke, Isabelle Magalhaes, Zuzana Potacova, Jonas Mattsson, Alexei Terman, Sam Ghazi, Nils Albiin, Nikolaos Kartalis, Peter Nilsson, Thomas Poiret, Liu Zhenjiang, Rainer Heuchel, Jochen M Schwenk, Johan Permert, Markus J Maeurer, Olle Ringden
We examined the immunologic effects of allogeneic hematopoietic stem cell transplantation (HSCT) in the treatment of pancreatic ductal adenocarcinoma, a deadly disease with a median survival of 24 months for resected tumors and a 5-year survival rate of 6%. After adjuvant chemotherapy, 2 patients with resected pancreatic ductal adenocarcinoma underwent HSCT with HLA-identical sibling donors. Comparable patients who underwent radical surgery, but did not have a donor, served as controls (n=6). Both patients developed humoral and cellular (ie, HLA-A*01:01-restricted) immune responses directed against 2 novel tumor-associated antigens (TAAs), INO80E and UCLH3 after HSCT...
March 23, 2017: Journal of Immunotherapy
https://www.readbyqxmd.com/read/28301141/reconstitution-and-substrate-specificity-of-the-radical-s-adenosyl-methionine-thiazole-c-methyltransferase-in-thiomuracin-biosynthesis
#12
Nilkamal Mahanta, Zhengan Zhang, Graham A Hudson, Wilfred A van der Donk, Douglas A Mitchell
Thiomuracin is a thiopeptide antibiotic with potent activity toward Gram-positive drug-resistant bacteria. Thiomuracin is biosynthesized from a precursor peptide, TbtA, by a complex array of posttranslational modifications. One of several intriguing transformations is the C-methylation of thiazole, occurring at an unactivated sp(2) carbon. Herein, we report the in vitro reconstitution of TbtI, the responsible radical S-adenosyl-methionine (rSAM) C-methyltransferase, which catalyzes the formation of 5-methylthiazole at a single site...
March 29, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28294069/wallet-neuritis-an-example-of-peripheral-sensitization
#13
Md Abu Bakar Siddiq, Israt Jahan, Sam Masihuzzaman
BACKGROUND: Wallet neuritis is an example of extra-spinal tunnel neuropathy concerning sciatic nerve. Its clinical appearance often gets confused with sciatica of lumbar spine origin. Wallet-induced chronic sciatic nerve constriction produces gluteal and ipsilateral lower extremity pain, tingling, and burning sensation. It was Lutz, first describing credit-card wallet sciatica in an Attorney, surfaced on Journal of American Medical Association (JAMA), 1978; however, the condition has not been well-studied in various other occupations...
March 9, 2017: Current Rheumatology Reviews
https://www.readbyqxmd.com/read/28282126/tuning-the-rectification-ratio-by-changing-the-electronic-nature-open-shell-and-closed-shell-in-donor-acceptor-self-assembled-monolayers
#14
Manuel Souto, Li Yuan, Dayana C Morales, Li Jiang, Imma Ratera, Christian A Nijhuis, Jaume Veciana
This Communication describes the mechanism of charge transport across self-assembled monolayers (SAMs) of two donor-acceptor systems consisting of a polychlorotriphenylmethyl (PTM) electron-acceptor moiety linked to an electron-donor ferrocene (Fc) unit supported by ultraflat template-stripped Au and contacted by a eutectic alloy of gallium and indium top contacts. The electronic and supramolecular structures of these SAMs were well characterized. The PTM unit can be switched between the nonradical and radical forms, which influences the rectification behavior of the junction...
March 16, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28252517/transanal-minimally-invasive-surgery-for-local-excision-of-benign-and-malignant-rectal-neoplasia-outcomes-from-200-consecutive-cases-with-midterm-follow-up
#15
Lawrence Lee, John P Burke, Teresa deBeche-Adams, George Nassif, Beatriz Martin-Perez, John R T Monson, Matthew R Albert, Sam B Atallah
OBJECTIVE: This study describes the outcomes for 200 consecutive transanal minimally invasive surgery (TAMIS) local excision (LE) for rectal neoplasia. BACKGROUND: TAMIS is an advanced transanal platform that can result in high quality LE of rectal neoplasia. METHODS: Consecutive patients from July 1, 2009 to December 31, 2015 from a prospective institutional registry were analyzed. Indication for TAMIS LE was endoscopically unresectable benign lesions or histologically favorable early rectal cancers...
March 1, 2017: Annals of Surgery
https://www.readbyqxmd.com/read/28191919/lysine-tryptophan-crosslinked-peptides-produced-by-radical-sam-enzymes-in-pathogenic-streptococci
#16
Kelsey R Schramma, Mohammad R Seyedsayamdost
Macrocycles represent a common structural framework in many naturally occurring peptides. Several strategies exist for macrocyclization, and the enzymes that incorporate them are of great interest, as they enhance our repertoire for creating complex molecules. We recently discovered a new peptide cyclization reaction involving a crosslink between the side chains of lysine and tryptophan that is installed by a radical SAM enzyme. Herein, we characterize relatives of this metalloenzyme from the pathogens Streptococcus agalactiae and Streptococcus suis...
March 3, 2017: ACS Chemical Biology
https://www.readbyqxmd.com/read/28164386/a-class-c-radical-s-adenosylmethionine-methyltransferase-synthesizes-8-methylmenaquinone
#17
Sascha Hein, Oliver Klimmek, Markus Polly, Melanie Kern, Jörg Simon
The membranous quinone/quinol pool is essential to the majority of life forms and has been widely used as an important biomarker in microbial taxonomy. In the anaerobic world, the most important quinones are menaquinone (MK) and a methylated form of MK, designated methylmenaquinone (MMK), which is anticipated to serve specifically in low-potential electron transport chains involved in anaerobic respiration. However, it has remained unclear how MMK is generated. Here, we show that a novel enzyme homologous to class C radical SAM methyltransferases (RSMTs) synthesizes MMK using MK as substrate...
February 6, 2017: Molecular Microbiology
https://www.readbyqxmd.com/read/28112859/the-catalytic-mechanism-of-the-class-c-radical-s-adenosylmethionine-methyltransferase-nosn
#18
Wei Ding, Yongzhen Li, Junfeng Zhao, Xinjian Ji, Tianlu Mo, Haocheng Qianzhu, Tao Tu, Zixin Deng, Yi Yu, Fener Chen, Qi Zhang
S-Adenosylmethionine (SAM) is one of the most common co-substrates in enzyme-catalyzed methylation reactions. Most SAM-dependent reactions proceed through an SN 2 mechanism, whereas a subset of them involves radical intermediates for methylating non-nucleophilic substrates. Herein, we report the characterization and mechanistic investigation of NosN, a class C radical SAM methyltransferase involved in the biosynthesis of the thiopeptide antibiotic nosiheptide. We show that, in contrast to all known SAM-dependent methyltransferases, NosN does not produce S-adenosylhomocysteine (SAH) as a co-product...
January 23, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28108243/tpx2-as-a-prognostic-indicator-and-potential-therapeutic-target-in-clear-cell-renal-cell-carcinoma
#19
Zachary A Glaser, Harold D Love, Shunhua Guo, Lan Gellert, Sam S Chang, Stanley Duke Herrell, Daniel A Barocas, David F Penson, Michael S Cookson, Peter E Clark
OBJECTIVES: Our aims were to determine if targeting protein for Xklp2 (TPX2) is correlated with clear cell renal cell carcinoma (ccRCC) histology and oncologic outcomes using The Cancer Genome Atlas (TCGA) and an institutional tissue microarray (TMA). METHODS: Clinicopathological data obtained from the TCGA consisted of 415 samples diagnosed with ccRCC. A TMA was constructed from tumors of 207 patients who underwent radical nephrectomy for ccRCC. TPX2 expression by immunohistochemistry on TMA was assessed by a genitourinary pathologist...
January 17, 2017: Urologic Oncology
https://www.readbyqxmd.com/read/28093141/re-utility-and-significance-of-ureteric-frozen-section-analysis-during-radical-cystectomy
#20
Sam S Chang
No abstract text is available yet for this article.
February 2017: Journal of Urology
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