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Berger JM, Alany A, Berchtold L, Puhr R, Friedrich A, Scheiner B, Prager GW, Preusser M, Berghoff AS, Bergen ES. Prognosticators of survival in patients with metastatic pancreatic cancer and ascites. ESMO Open 2023; 8:102048. [PMID: 37977000 PMCID: PMC10774951 DOI: 10.1016/j.esmoop.2023.102048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND Identification of factors associated with survival after ascites diagnosis in metastatic pancreatic cancer (mPC) patients may guide treatment decisions and help to maintain quality of life in this highly symptomatic patient collective. PATIENTS AND METHODS All patients treated for mPC at the Medical University of Vienna between 2010 and 2019 developing ascites throughout their course of disease were identified by retrospective chart review. General risk factors, metastatic sites, systemic inflammation and liver function parameters, as well as type of treatment after ascites diagnosis were investigated for associations with survival. RESULTS One hundred and seventeen mPC patients with ascites were included in this study. Median time from mPC to ascites diagnosis was 8.9 months (range 0-99 months) and median overall survival (OS) after ascites diagnosis was 27.4 days (range 21.3-42.6 days). Identified prognostic factors at ascites diagnosis independently associated with an impaired OS were presence of liver metastases [hazard ratio (HR): 2.07, 95% confidence interval (CI) 1.13-3.79, P = 0.018), peritoneal carcinomatosis (HR: 1.74, 95% CI 1.11-2.71, P = 0.015), and portal vein obstruction (HR: 2.52, 95% CI 1.29-4.90, P = 0.007). Compared with best supportive care, continuation of systemic therapy after ascites diagnosis was independently associated with survival (HR: 0.35, 95% CI 0.20-0.61, P < 0.001) with a median OS of 62 days (95% CI 51-129 days, P < 0.001) versus 16 days (95% CI 11-24 days), respectively. CONCLUSIONS Liver and peritoneal metastases as well as portal vein obstruction were found to be prognostic factors after ascites diagnosis in mPC patients. Continuation of systemic therapy after ascites diagnosis was associated with a longer OS, which needs to be evaluated in larger clinical trials including quality-of-life assessment.
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Affiliation(s)
- J M Berger
- Division of Oncology, Department of Medicine I, Medical University of Vienna, Vienna; Christian Doppler Laboratory for Personalized Immunotherapy, Department of Medicine I, Medical University of Vienna, Vienna
| | - A Alany
- Division of Oncology, Department of Medicine I, Medical University of Vienna, Vienna
| | - L Berchtold
- Division of Oncology, Department of Medicine I, Medical University of Vienna, Vienna
| | - R Puhr
- Division of Oncology, Department of Medicine I, Medical University of Vienna, Vienna
| | - A Friedrich
- Division of Oncology, Department of Medicine I, Medical University of Vienna, Vienna
| | - B Scheiner
- Division of Gastroenterology and Hepatology, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - G W Prager
- Division of Oncology, Department of Medicine I, Medical University of Vienna, Vienna
| | - M Preusser
- Division of Oncology, Department of Medicine I, Medical University of Vienna, Vienna; Christian Doppler Laboratory for Personalized Immunotherapy, Department of Medicine I, Medical University of Vienna, Vienna
| | - A S Berghoff
- Division of Oncology, Department of Medicine I, Medical University of Vienna, Vienna; Christian Doppler Laboratory for Personalized Immunotherapy, Department of Medicine I, Medical University of Vienna, Vienna
| | - E S Bergen
- Division of Oncology, Department of Medicine I, Medical University of Vienna, Vienna.
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Abstract
Cardiovascular diseases (CVDs) are the most common cause of death in patients with nonalcoholic fatty liver disease (NAFLD) and dyslipidemia is considered at least partially responsible for the increased CVD risk in NAFLD patients. The aim of the present study is to understand how hepatic de novo lipogenesis influences hepatic cholesterol content as well as its effects on the plasma lipid levels. Hepatic lipogenesis was induced in mice by feeding a fat-free/high-sucrose (FF/HS) diet and the metabolic pathways associated with cholesterol were then analyzed. Both liver triglyceride and cholesterol contents were significantly increased in mice fed an FF/HS diet. Activation of fatty acid synthesis driven by the activation of sterol regulatory element binding protein (SREBP)-1c resulted in the increased liver triglycerides. The augmented cholesterol content in the liver could not be explained by an increased cholesterol synthesis, which was decreased by the FF/HS diet. HMGCoA reductase protein level was decreased in mice fed an FF/HS diet. We found that the liver retained more cholesterol through a reduced excretion of bile acids, a reduced fecal cholesterol excretion, and an increased cholesterol uptake from plasma lipoproteins. Very low-density lipoproteintriglyceride and -cholesterol secretion were increased in mice fed an FF/HS diet, which led to hypertriglyceridemia and hypercholesterolemia in Ldlr-/- mice, a model that exhibits a more human like lipoprotein profile. These findings suggest that dietary cholesterol intake and cholesterol synthesis rates cannot only explain the hypercholesterolemia associated with NAFLD, and that the control of fatty acid synthesis should be considered for the management of dyslipidemia.
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Affiliation(s)
- Jean-Mathieu Berger
- Departments of Internal Medicine and Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Young-Ah Moon
- Department of Molecular Medicine, Inha University College of Medicine, Incheon 22212, Korea
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Berger JM, Loza Valdes A, Gromada J, Anderson N, Horton JD. Inhibition of PCSK9 does not improve lipopolysaccharide-induced mortality in mice. J Lipid Res 2017; 58:1661-1669. [PMID: 28600283 PMCID: PMC5538287 DOI: 10.1194/jlr.m076844] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/01/2017] [Indexed: 12/11/2022] Open
Abstract
Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a secreted protein that targets LDL receptors (LDLRs) for degradation in liver. Blocking the interaction of PCSK9 with the LDLR potently reduces plasma LDL cholesterol levels and cardiovascular events. Recently, it has been suggested that inhibition of PCSK9 might also improve outcomes in mice and humans with sepsis, possibly by increasing LDLR-mediated clearance of endotoxins. Sepsis is a complication of a severe microbial infection that has shared pathways with lipid metabolism. Here, we tested whether anti-PCSK9 antibodies prevent death from lipopolysaccharide (LPS)-induced endotoxemia. Mice were administered PCSK9 antibodies prior to, or shortly after, injecting LPS. In both scenarios, the administration of PCSK9 antibodies did not alter endotoxemia-induced mortality. Afterward, we determined whether the complete absence of PCSK9 improved endotoxemia-induced mortality in mice with the germ-line deletion of Pcsk9. Similarly, PCSK9 knockout mice were not protected from LPS-induced death. To determine whether low LDLR expression increased LPS-induced mortality, Ldlr−/− mice and PCSK9 transgenic mice were studied after injection of LPS. Endotoxemia-induced mortality was not altered in either mouse model. In a human cohort, we observed no correlation between plasma inflammation markers with total cholesterol levels, LDL cholesterol, and PCSK9. Combined, our data demonstrate that PCSK9 inhibition provides no protection from LPS-induced mortality in mice.
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Affiliation(s)
- Jean-Mathieu Berger
- Departments of Internal Medicine and Molecular Genetics University of Texas Southwestern Medical Center, Dallas, TX
| | - Angel Loza Valdes
- Departments of Internal Medicine and Molecular Genetics University of Texas Southwestern Medical Center, Dallas, TX
| | | | - Norma Anderson
- Departments of Internal Medicine and Molecular Genetics University of Texas Southwestern Medical Center, Dallas, TX
| | - Jay D Horton
- Departments of Internal Medicine and Molecular Genetics University of Texas Southwestern Medical Center, Dallas, TX; Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX.
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Berger JM, Vaillant N, Le May C, Calderon C, Brégeon J, Prieur X, Hadchouel J, Loirand G, Cariou B. PCSK9-deficiency does not alter blood pressure and sodium balance in mouse models of hypertension. Atherosclerosis 2015; 239:252-9. [DOI: 10.1016/j.atherosclerosis.2015.01.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 12/30/2014] [Accepted: 01/18/2015] [Indexed: 01/11/2023]
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Abstract
Bioactivity guided fractionation of an EtOAc extract from Psoralidium tenuiflorum (Pursh) Rydb. (family : Fabaceae) yielded the known compound bakuchiol as a racemic mixture. This compound was purified by liquid-liquid partitioning and chromatography followed by NMR and GCMS characterisation. This compound exhibited Staphylococcus epidermidis cytotoxicity. COSY and HETCOR spectra of the isolated bakuchiol indicated two disagreements with previously reported NMR structural assignments; reassignments are described herein. Long-term storage of bakuchiol resulted in degradation to 4-hydroxybenzaldehyde, which was purified and characterised.
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Affiliation(s)
- P-J Hsu
- Department of Chemistry and Biochemistry, Montclair State University, Montclair, NJ 07043, USA
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Murillo AC, Li HY, Alber T, Baker EN, Berger JM, Cherney LT, Cherney MM, Cho YS, Eisenberg D, Garen CR, Goulding CW, Hung LW, Ioerger TR, Jacobs WR, James MNG, Kim C, Krieger I, Lott JS, Sankaranarayanan R, Segelke BW, Terwilliger TC, Wang F, Wang S, Sacchettini JC. High throughput crystallography of TB drug targets. Infect Disord Drug Targets 2007; 7:127-139. [PMID: 17970224 DOI: 10.2174/187152607781001853] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Tuberculosis (TB) infects one-third of the world population. Despite 50 years of available drug treatments, TB continues to increase at a significant rate. The failure to control TB stems in part from the expense of delivering treatment to infected individuals and from complex treatment regimens. Incomplete treatment has fueled the emergence of multi-drug resistant (MDR) strains of Mycobacterium tuberculosis (Mtb). Reducing non-compliance by reducing the duration of chemotherapy will have a great impact on TB control. The development of new drugs that either kill persisting organisms, inhibit bacilli from entering the persistent phase, or convert the persistent bacilli into actively growing cells susceptible to our current drugs will have a positive effect. We are taking a multidisciplinary approach that will identify and characterize new drug targets that are essential for persistent Mtb. Targets are exposed to a battery of analyses including microarray experiments, bioinformatics, and genetic techniques to prioritize potential drug targets from Mtb for structural analysis. Our core structural genomics pipeline works with the individual laboratories to produce diffraction quality crystals of targeted proteins, and structural analysis will be completed by the individual laboratories. We also have capabilities for functional analysis and the virtual ligand screening to identify novel inhibitors for target validation. Our overarching goals are to increase the knowledge of Mtb pathogenesis using the TB research community to drive structural genomics, particularly related to persistence, develop a central repository for TB research reagents, and discover chemical inhibitors of drug targets for future development of lead compounds.
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Affiliation(s)
- A C Murillo
- Texas A&M University, Department of Biochemistry and Biophysics, College Station 77843-2128, USA
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Hagenbach U, Luz S, Ghafoor N, Berger JM, Grotenhermen F, Brenneisen R, Mäder M. The treatment of spasticity with Delta9-tetrahydrocannabinol in persons with spinal cord injury. Spinal Cord 2006; 45:551-62. [PMID: 17043680 DOI: 10.1038/sj.sc.3101982] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
STUDY DESIGN Open label study to determine drug dose for a randomized double-blind placebo-controlled parallel study. OBJECTIVES To assess the efficacy and side effects of oral Delta(9)-tetrahydrocannabinol (THC) and rectal THC-hemisuccinate (THC-HS) in SCI patients. SETTING REHAB Basel, Switzerland. METHOD Twenty-five patients with SCI were included in this three-phase study with individual dose adjustment, each consisting of 6 weeks. Twenty-two participants received oral THC open label starting with a single dose of 10 mg (Phase 1, completed by 15 patients). Eight subjects received rectal THC-HS (Phase 2, completed by seven patients). In Phase 3, six patients were treated with oral THC and seven with placebo. Major outcome parameters were the spasticity sum score (SSS) using the Modified Ashworth Scale (MAS) and self-ratings of spasticity. RESULTS Mean daily doses were 31 mg with THC and 43 mg with THC-HS. Mean SSS for THC decreased significantly from 16.72 (+/-7.60) at baseline to 8.92 (+/-7.14) on day 43. Similar improvement was seen with THC-HS. We observed a significant improvement of SSS with active drug (P=0.001) in the seven subjects who received oral THC in Phase 1 and placebo in Phase 3. Major reasons for drop out were increase of pain and psychological side effects. CONCLUSION THC is an effective and safe drug in the treatment of spasticity. At least 15-20 mg per day were needed to achieve a therapeutic effect.
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Affiliation(s)
- U Hagenbach
- REHAB Basel, Centre for Spinal Cord Injury and Severe Head Injury, Basel, Switzerland
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8
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Abstract
DNA topos (topoisomerases) are complex, multisubunit enzymes that remodel DNA topology. Members of the type II topo family function by passing one segment of duplex DNA through a transient break in another, a process that consumes two molecules of ATP and requires the co-ordinated action of multiple domains. Recent structural data on type II topo ATPase regions, which activate and enforce the directionality of DNA strand passage, have highlighted how ATP physically controls the catalytic cycle of the enzyme. Structural and biochemical studies of specialized DNA-binding domains in two paralogous bacterial type IIA topos (DNA gyrase and topo IV) show how these enzymes selectively negatively supercoil or decatenate DNA. Taken together, these findings expand our understanding of how disparate functional elements work together to co-ordinate the type II topo mechanism.
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Affiliation(s)
- A J Schoeffler
- Department of Molecular and Cell Biology, 237 Hildebrand Hall #3206, University of California, Berkeley, CA 94720-3206, USA
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Abdel-Kader M, Hoch J, Berger JM, Evans R, Miller JS, Wisse JH, Mamber SW, Dalton JM, Kingston DG. Two bioactive saponins from Albizia subdimidiata from the Suriname rainforest. J Nat Prod 2001; 64:536-539. [PMID: 11325245 DOI: 10.1021/np000295u] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Bioassay-guided fractionation of a methanol extract of Albizia subdimidiata using the engineered yeast strains 1138, 1140, 1353, and Sc7 of Saccharomyces cerevisiae as the bioassay tool resulted in the isolation of the two active saponins 1 and 2; one of these, albiziatrioside A (1), is described for the first time. The structures of 1 and 2 were established on the basis of HRMS, 1D and 2D NMR spectral data, and GC--MS analysis of the sugar units. Both isolated compounds showed significant cytotoxicity against the A2780 cell line.
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Affiliation(s)
- M Abdel-Kader
- Department of Chemistry, M/C 0212, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
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Gunatilaka AA, Berger JM, Evans R, Miller JS, Wisse JH, Neddermann KM, Bursuker I, Kingston DG. Isolation, synthesis, and structure-activity relationships of bioactive benzoquinones from Miconia lepidota from the Suriname rainforest. J Nat Prod 2001; 64:2-5. [PMID: 11170656 DOI: 10.1021/np000219r] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Bioactivity-directed fractionation of an EtOAc extract from the leaves of Miconia lepidota afforded the two benzoquinones 2-methoxy-6-heptyl-1,4-benzoquinone (1) and 2-methoxy-6-pentyl-1,4-benzoquinone (primin) (2). This is the first reported isolation of 1. Both quinones 1 and 2 exhibited activity toward mutant yeast strains based on Saccharomyces cerevisiae, indicative of their cytotoxicity and potential anticancer activity. A number of previously synthesized and new analogues were prepared and tested in the same strains. Compounds 1, 2, 2-methoxy-6-butyl-1,4-benzoquinone (5), and 2-methoxy-6-decyl-1,4-benzoquinone (6) were tested in two cytotoxicity assays. In the M109 tumor cell lines, quinones 1, 2, and 6 had an IC(50) value of 10 microg/mL. In the A2780 cell line, compounds 1, 2 and 5 had IC(50) values of 7.9, 2.9, and 3.2 microg/mL, respectively.
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Affiliation(s)
- A A Gunatilaka
- Department of Chemistry, M/C 0212, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA
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Raisin C, Berger JM, Robin-Kandare S. UPS and XPS spectra of CdF2and SrF2and interpretation of optical properties of these compounds. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/13/9/028] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Abstract
Proteins often require cofactors to perform their biological functions and must fold in the presence of their cognate ligands. Using circular dichroism spectroscopy. we investigated the effects of divalent metal binding upon the folding pathway of Escherichia coli RNase HI. This enzyme binds divalent metal in its active site, which is proximal to the folding core of RNase HI as defined by hydrogen/deuterium exchange studies. Metal binding increases the apparent stability of native RNase HI chiefly by reducing the unfolding rate. As with the apo-form of the protein, refolding from high denaturant concentrations in the presence of Mg2+ follows three-state kinetics: formation of a rapid burst phase followed by measurable single exponential kinetics. Therefore, the overall folding pathway of RNase HI is minimally perturbed by the presence of metal ions. Our results indicate that the metal cofactor enters the active site pocket only after the enzyme reaches its native fold, and therefore, divalent metal binding stabilizes the protein by decreasing its unfolding rate. Furthermore, the binding of the cofactor is dependent upon a carboxylate critical for activity (Asp10). A mutation in this residue (D10A) alters the folding kinetics in the absence of metal ions such that they are similar to those observed for the unaltered enzyme in the presence of metal.
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Affiliation(s)
- E R Goedken
- Department of Molecular and Cell Biology, University of California, Berkeley 94720, USA
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Liu J, Smith CL, DeRyckere D, DeAngelis K, Martin GS, Berger JM. Structure and function of Cdc6/Cdc18: implications for origin recognition and checkpoint control. Mol Cell 2000; 6:637-48. [PMID: 11030343 DOI: 10.1016/s1097-2765(00)00062-9] [Citation(s) in RCA: 183] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cdc6/Cdc18 is a conserved and essential component of prereplication complexes. The 2.0 A crystal structure of an archaeal Cdc6 ortholog, in conjunction with a mutational analysis of the homologous Cdc18 protein from Schizosaccharomyces pombe, reveals novel aspects of Cdc6/Cdc18 function. Two domains of Cdc6 form an AAA+-type nucleotide binding fold that is observed bound to Mg.ADP. A third domain adopts a winged-helix fold similar to known DNA binding modules. Sequence comparisons show that the winged-helix domain is conserved in Orc1, and mutagenesis data demonstrate that this region of Cdc6/Cdc18 is required for function in vivo. Additional mutational analyses suggest that nucleotide binding and/or hydrolysis by Cdc6/Cdc18 is required not only for progression through S phase, but also for maintenance of checkpoint control during S phase.
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Affiliation(s)
- J Liu
- Department of Molecular and Cell Biology, University of California, Berkeley 94720, USA
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Minor DL, Lin YF, Mobley BC, Avelar A, Jan YN, Jan LY, Berger JM. The polar T1 interface is linked to conformational changes that open the voltage-gated potassium channel. Cell 2000; 102:657-70. [PMID: 11007484 DOI: 10.1016/s0092-8674(00)00088-x] [Citation(s) in RCA: 153] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Kv voltage-gated potassium channels share a cytoplasmic assembly domain, T1. Recent mutagenesis of two T1 C-terminal loop residues implicates T1 in channel gating. However, structural alterations of these mutants leave open the question concerning direct involvement of T1 in gating. We find in mammalian Kv1.2 that gating depends critically on residues at complementary T1 surfaces in an unusually polar interface. An isosteric mutation in this interface causes surprisingly little structural alteration while stabilizing the closed channel and increasing the stability of T1 tetramers. Replacing T1 with a tetrameric coiled-coil destabilizes the closed channel. Together, these data suggest that structural changes involving the buried polar T1 surfaces play a key role in the conformational changes leading to channel opening.
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Affiliation(s)
- D L Minor
- Howard Hughes Medical Institute and Department of Physiology, University of California, San Francisco 94143, USA.
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Abstract
All cellular organisms use specialized RNA polymerases called "primases" to synthesize RNA primers for the initiation of DNA replication. The high-resolution crystal structure of a primase, comprising the catalytic core of the Escherichia coli DnaG protein, was determined. The core structure contains an active-site architecture that is unrelated to other DNA or RNA polymerase palm folds, but is instead related to the "toprim" fold. On the basis of the structure, it is likely that DnaG binds nucleic acid in a groove clustered with invariant residues and that DnaG is positioned within the replisome to accept single-stranded DNA directly from the replicative helicase.
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Affiliation(s)
- J L Keck
- Department of Molecular and Cell Biology, University of California, Berkeley, 229 Stanley Hall, no. 3206, Berkeley, CA 94720, USA
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Berger JM, Ryan A, Vadivelu N, Merriam P, Rever L, Harrison P. Ketamine-fentanyl-midazolam infusion for the control of symptoms in terminal life care. Am J Hosp Palliat Care 2000; 17:127-34. [PMID: 11406957 DOI: 10.1177/104990910001700213] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In this report, we describe nine terminally ill patients with metastatic cancer who were treated with an intravenous infusion consisting of ketamine (2 mg/ml)/fentanyl (5 micrograms/ml)/midazolam (0.1 mg/ml) (K/F/M) to control pain after traditional analgesic therapies were unsuccessful. In addition to pain, all patients exhibited some symptoms of cognitive compromise and agitation. After initiation of the K/F/M infusion, all patients exhibited some degree of qualitative improvement in these symptoms as well as in overall pain control. We feel that these observations warrant reporting of the efficacy of this infusion for the treatment of uncontrolled pain and agitation in terminally ill patients when the traditional methods of pain control are inadequate.
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Affiliation(s)
- J M Berger
- Department of Anesthesiology, Pain Management Service, University of Southern California, Keck School of Medicine, Los Angeles, California, USA
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Abstract
Several decades of research have delineated the roles of many proteins central to DNA replication. Here we present a structural perspective of this work spanning the past 15 years and highlight several recent advances in the field.
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Affiliation(s)
- J L Keck
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
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Nichols MD, DeAngelis K, Keck JL, Berger JM. Structure and function of an archaeal topoisomerase VI subunit with homology to the meiotic recombination factor Spo11. EMBO J 1999; 18:6177-88. [PMID: 10545127 PMCID: PMC1171681 DOI: 10.1093/emboj/18.21.6177] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In all organisms, type II DNA topoisomerases are essential for untangling chromosomal DNA. We have determined the structure of the DNA-binding core of the Methanococcus jannaschii DNA topoisomerase VI A subunit at 2.0 A resolution. The overall structure of this subunit is unique, demonstrating that archaeal type II enzymes are distinct from other type II topoisomerases. However, the core structure contains a pair of domains that are also found in type IA and classic type II topoisomerases. Together, these regions may form the basis of a DNA cleavage mechanism shared among these enzymes. The core A subunit is a dimer that contains a deep groove that spans both protomers. The dimer architecture suggests that DNA is bound in the groove, across the A subunit interface, and that the two monomers separate during DNA transport. The A subunit of topoisomerase VI is homologous to the meiotic recombination factor, Spo11, and this structure can serve as a template for probing Spo11 function in eukaryotes.
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Affiliation(s)
- M D Nichols
- Department of Molecular and Cell Biology, University of California at Berkeley, 229 Stanley Hall-#3206, Berkeley, CA 94720, USA
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20
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Abstract
DNA topoisomerases are proteins that regulate DNA topology in cells through selective cycles of DNA cleavage, manipulation, and religation. Two papers describe an ensemble of different protein conformations and nucleotide-protein complexes of Escherichia coli topoisomerase. These results lead to new insights about how this enzyme recognizes DNA and catalyzes supercoil relaxation.
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Abstract
BACKGROUND The hexameric helicase DnaB unwinds the DNA duplex at the Escherichia coli chromosome replication fork. Although the mechanism by which DnaB both couples ATP hydrolysis to translocation along DNA and denatures the duplex is unknown, a change in the quaternary structure of the protein involving dimerization of the N-terminal domain has been observed and may occur during the enzymatic cycle. This N-terminal domain is required both for interaction with other proteins in the primosome and for DnaB helicase activity. Knowledge of the structure of this domain may contribute to an understanding of its role in DnaB function. RESULTS We have determined the structure of the N-terminal domain of DnaB crystallographically. The structure is globular, highly helical and lacks a close structural relative in the database of known protein folds. Conserved residues and sites of dominant-negative mutations have structurally significant roles. Each asymmetric unit in the crystal contains two independent and identical copies of a dimer of the DnaB N-terminal domain. CONCLUSIONS The large-scale domain or subunit reorientation that is seen in DnaB by electron microscopy might result from the formation of a true twofold symmetric dimer of N-terminal domains, while maintaining a head-to-tail arrangement of C-terminal domains. The N-terminal domain of DnaB is the first region of a hexameric DNA replicative helicase to be visualized at high resolution. Comparison of this structure to the analogous region of the Rho RNA/DNA helicase indicates that the N-terminal domains of these hexameric helicases are structurally dissimilar.
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Affiliation(s)
- D Fass
- Whitehead Institute, Cambridge, Massachusetts 02142, USA
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22
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Abstract
The E. coli Rho protein disengages newly transcribed RNA from its DNA template, helping terminate certain transcripts. We have determined the X-ray crystal structure of the RNA-binding domain of Rho complexed to an RNA ligand. Filters that screen both ligand size and chemical functionality line the primary nucleic acid-binding site, imparting sequence specificity to a generic single-stranded nucleic acid-binding fold and explaining the preference of Rho for cytosine-rich RNA. The crystal packing reveals two Rho domain protomers bound to a single RNA with a single base spacer, suggesting that the strong RNA-binding sites of Rho may arise from pairing of RNA-binding modules. Dimerization of symmetric subunits on an asymmetric ligand is developed as a model for allosteric control in the action of the intact Rho hexamer.
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Affiliation(s)
- C E Bogden
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Massachusetts 02142, USA
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23
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Abstract
Type II DNA topoisomerases mediate the passage of one DNA duplex through a transient break in another, an event essential for chromosome segregation and cell viability. The active sites of the type II topoisomerase dimer associate covalently with the DNA break-points and must separate by at least the width of the second DNA duplex to accommodate transport. A new structure of the Saccharomyces cerevisiae topoisomerase II DNA-binding and cleavage core suggests that in addition to conformational changes in the DNA-opening platform, a dramatic reorganization of accessory domains may occur during catalysis. These conformational differences have implications for both the DNA-breaking and duplex-transport events in the topo II reaction mechanism, suggest a mechanism by which two distinct drug-resistance loci interact, and illustrate the scope of structural changes in the cycling of molecular machines.
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Affiliation(s)
- D Fass
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02140, USA
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24
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Abstract
Many viruses regulate translation of polycistronic mRNA using a -1 ribosomal frameshift induced by an RNA pseudoknot. A pseudoknot has two stems that form a quasi-continuous helix and two connecting loops. A 1.6 A crystal structure of the beet western yellow virus (BWYV) pseudoknot reveals rotation and a bend at the junction of the two stems. A loop base is inserted in the major groove of one stem with quadruple-base interactions. The second loop forms a new minor-groove triplex motif with the other stem, involving 2'-OH and triple-base interactions, as well as sodium ion coordination. Overall, the number of hydrogen bonds stabilizing the tertiary interactions exceeds the number involved in Watson-Crick base pairs. This structure will aid mechanistic analyses of ribosomal frameshifting.
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Affiliation(s)
- L Su
- Department of Biology, Massachusetts Institute of Technology, Cambridge 02139, USA
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25
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Abstract
Over the last several years topoisomerases have finally begun to yield to high-resolution structural studies. These models have greatly aided our understanding of the mechanisms of topoisomerase catalysis and drug interactions. This review will cover advances in the structural biology of topoisomerases and discuss their implications for topoisomerase function.
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Affiliation(s)
- J M Berger
- Division of Biochemistry and Molecular Biology, Department of Molecular and Cellular Biology, 229 Stanley Hall, University of California, Berkeley, Berkeley, CA 94720, USA
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26
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Berger JM, Fass D, Wang JC, Harrison SC. Structural similarities between topoisomerases that cleave one or both DNA strands. Proc Natl Acad Sci U S A 1998; 95:7876-81. [PMID: 9653108 PMCID: PMC20897 DOI: 10.1073/pnas.95.14.7876] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/24/1998] [Indexed: 02/08/2023] Open
Abstract
Type IA and type II DNA topoisomerases are distinguished by their ability to cleave one or two strands, respectively, of a DNA duplex. Both types have been proposed to use an "enzyme-bridging" mechanism, in which a break is formed in a DNA strand and a gap is opened between the broken pieces to allow passage of a second DNA strand or duplex segment. Although the type IA and type II topoisomerase structures appear overall quite different from one another, unexpected similarities between several structural elements suggest that members of the two subfamilies may use comparable mechanisms to bind and cleave DNA.
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Affiliation(s)
- J M Berger
- Whitehead Institute, 9 Cambridge Center, Cambridge, MA 02142, USA
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27
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Singh M, Berger B, Kim PS, Berger JM, Cochran AG. Computational learning reveals coiled coil-like motifs in histidine kinase linker domains. Proc Natl Acad Sci U S A 1998; 95:2738-43. [PMID: 9501159 PMCID: PMC19638 DOI: 10.1073/pnas.95.6.2738] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The recent rapid growth of protein sequence databases is outpacing the capacity of researchers to biochemically and structurally characterize new proteins. Accordingly, new methods for recognition of motifs and homologies in protein primary sequences may be useful in determining how these proteins might function. We have applied such a method, an iterative learning algorithm, to analyze possible coiled coil domains in histidine kinase receptors. The potential coiled coils have not yet been structurally characterized in any histidine kinase, and they appear outside previously noted kinase homology regions. The learning algorithm uses a combination of established sequence patterns in known coiled coil proteins and histidine kinase sequence data to learn to recognize efficiently this coiled coil-like motif in the histidine kinases. The common appearance of the structural motif in a functionally important part of the receptors suggests hypotheses for kinase regulation and signal transduction.
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Affiliation(s)
- M Singh
- Center for Discrete Mathematics and Theoretical Computer Science (DIMACS) and Department of Computer Science, Princeton University, Princeton, NJ 08544, USA
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28
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Abstract
Type II DNA topoisomerases are enzymes capable of passing one DNA duplex through another. A combination of structural and biochemical analyses is illuminating the mechanistic details of this transport reaction, revealing the sites of DNA and nucleotide binding and the existence of large-scale domain motions.
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Affiliation(s)
- J M Berger
- Whitehead Institute, Cambridge, MA 02142, USA.
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29
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Fass D, Davey RA, Hamson CA, Kim PS, Cunningham JM, Berger JM. Structure of a murine leukemia virus receptor-binding glycoprotein at 2.0 angstrom resolution. Science 1997; 277:1662-6. [PMID: 9287219 DOI: 10.1126/science.277.5332.1662] [Citation(s) in RCA: 175] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
An essential step in retrovirus infection is the binding of the virus to its receptor on a target cell. The structure of the receptor-binding domain of the envelope glycoprotein from Friend murine leukemia virus was determined to 2.0 angstrom resolution by x-ray crystallography. The core of the domain is an antiparallel beta sandwich, with two interstrand loops forming a helical subdomain atop the sandwich. The residues in the helical region, but not in the beta sandwich, are highly variable among mammalian C-type retroviruses with distinct tropisms, indicating that the helical subdomain determines the receptor specificity of the virus.
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Affiliation(s)
- D Fass
- Howard Hughes Medical Institute, Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
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30
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Abstract
The low-density lipoprotein receptor (LDLR) is responsible for the uptake of cholesterol-containing lipoprotein particles into cells. The amino-terminal region of LDLR, which consists of seven tandemly repeated, approximately 40-amino-acid, cysteine-rich modules (LDL-A modules), mediates binding to lipoproteins. LDL-A modules are biologically ubiquitous domains, found in over 100 proteins in the sequence database. The structure of ligand-binding repeat 5 (LR5) of the LDLR, determined to 1.7 A resolution by X-ray crystallography and presented here, contains a calcium ion coordinated by acidic residues that lie at the carboxy-terminal end of the domain and are conserved among LDL-A modules. Naturally occurring point mutations found in patients with the disease familial hypercholesterolaemia alter residues that directly coordinate Ca2+ or that serve as scaffolding residues of LR5.
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Affiliation(s)
- D Fass
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge 02142, USA
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31
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Abstract
The envelope glycoprotein of human immunodeficiency virus type 1 (HIV-1) consists of a complex of gp120 and gp41. gp120 determines viral tropism by binding to target-cell receptors, while gp41 mediates fusion between viral and cellular membranes. Previous studies identified an alpha-helical domain within gp41 composed of a trimer of two interacting peptides. The crystal structure of this complex, composed of the peptides N36 and C34, is a six-helical bundle. Three N36 helices form an interior, parallel coiled-coil trimer, while three C34 helices pack in an oblique, antiparallel manner into highly conserved, hydrophobic grooves on the surface of this trimer. This structure shows striking similarity to the low-pH-induced conformation of influenza hemagglutinin and likely represents the core of fusion-active gp41. Avenues for the design/discovery of small-molecule inhibitors of HIV infection are directly suggested by this structure.
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Affiliation(s)
- D C Chan
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA
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32
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Abstract
Recent biochemical and crystallographic results suggest that a type II DNA topoisomerase acts as an ATP-modulated clamp with two sets of jaws at opposite ends: a DNA-bound enzyme can admit a second DNA through one set of jaws; upon binding ATP, this DNA is passed through an enzyme-mediated opening in the first DNA and expelled from the enzyme through the other set of jaws. Experiments based on the introduction of reversible disulfide links across one dimer interface of yeast DNA topoisomerase II have confirmed this mechanism. The second DNA is found to enter the enzyme through the gate formed by the N-terminal parts of the enzyme and leave it through the gate close to the C termini.
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Affiliation(s)
- J Roca
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
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33
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Abstract
Type II DNA topoisomerases are enzymes that are capable of transporting one duplex DNA through another. Recent experimental results, including the structure of a fragment of yeast topoisomerase II, have provided new insights into the mechanism of the strand passage reaction. Other results have begun to define the role of ATP in the catalytic cycle and illuminate how DNA breaks mediated by topoisomerase II can occur.
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Affiliation(s)
- J M Berger
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
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34
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Abstract
The crystal structure of a large fragment of yeast type II DNA topoisomerase reveals a heart-shaped dimeric protein with a large central hole. It provides a molecular model of the enzyme as an ATP-modulated clamp with two sets of jaws at opposite ends, connected by multiple joints. An enzyme with bound DNA can admit a second DNA duplex through one set of jaws, transport it through the cleaved first duplex, and expel it through the other set of jaws.
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Affiliation(s)
- J M Berger
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
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35
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Roca J, Ishida R, Berger JM, Andoh T, Wang JC. Antitumor bisdioxopiperazines inhibit yeast DNA topoisomerase II by trapping the enzyme in the form of a closed protein clamp. Proc Natl Acad Sci U S A 1994; 91:1781-5. [PMID: 8127881 PMCID: PMC43247 DOI: 10.1073/pnas.91.5.1781] [Citation(s) in RCA: 269] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The mechanism of inhibition of eukaryotic DNA topoisomerase II [DNA topoisomerase (ATP-hydrolyzing), EC 5.99.1.3] by a member of the bisdioxopiperazine family of anticancer drugs, ICRF-193, was investigated by using purified yeast DNA topoisomerase II. In the absence of ATP, ICRF-193 has little effect on the binding of the enzyme to various forms of DNA. In the presence of ATP, the drug converts the enzyme to a form incapable of binding circular DNA. Incubation of a preformed circular DNA-enzyme complex with ICRF-193 and ATP converts the complex to a form stable in molar concentrations of salt. These results can be interpreted in terms of the ATP-modulated protein-clamp model of type II DNA topoisomerases [Roca, J. & Wang, J. C. (1992) Cell 71, 833-840]; ICRF-193 can bind to the closed-clamp form of the enzyme and prevents its conversion to the open-clamp form. This interpretation is further supported by the finding that whereas both ATP and the drug are needed to form the salt-stable circular DNA-enzyme complex, ATP is not needed for maintaining this complex; furthermore, a signature of the closed-clamp form of the enzyme, Staphylococcus aureus strain V8 endoproteinase cleavage site at Glu-680, is observed if the enzyme is incubated with both ATP and ICRF-193. Inhibition of interconversion between the open- and closed-clamp forms of type II DNA topoisomerases offers a new mechanism in the selection and design of therapeutics targeting this class of enzymes.
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Affiliation(s)
- J Roca
- Department of Biochemistry and Molecular Biology, Harvard University, Cambridge, MA 02138
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36
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Roca J, Berger JM, Wang JC. On the simultaneous binding of eukaryotic DNA topoisomerase II to a pair of double-stranded DNA helices. J Biol Chem 1993; 268:14250-5. [PMID: 8390987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Stabilization of crossings of pairs of DNA helices by binding of eukaryotic DNA topoisomerase II was studied by two types of experiments. In one, mixtures of yeast DNA topoisomerase II and supercoiled DNA were incubated with vaccinia virus topoisomerase, and the linking numbers of the DNA products were measured to quantitate supercoils that were constrained by the stoichiometrically bound yeast enzyme molecules; in parallel, the same yeast enzyme-supercoiled DNA mixtures were incubated with a nonhydrolyzable ATP analog AMPPNP (adenosine 5'-(beta, gamma-imido)triphosphate) instead of the vaccinia enzyme, and DNA linking number changes following the addition of AMPPNP were measured to monitor DNA transport mediated by the yeast enzyme and AMPPNP. In the second type of experiments, formation of knotted DNA rings by the addition of AMPPNP to mixtures of yeast DNA topoisomerase II and different topological forms of DNA rings was studied. These experiments indicate that binding of yeast DNA topoisomerase II to DNA crossings is significant, especially in low salt media containing Mg(II), and that this mode of binding strongly affects DNA knotting. It appears, however, that stabilization of DNA crossovers by the eukaryotic type II enzyme is not directly related to its DNA transport activity.
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Affiliation(s)
- J Roca
- Department of Biochemistry and Molecular Biology, Harvard University, Cambridge, Massachusetts 02138
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37
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Dercksen DP, Berger JM. [Rickets-like bone changes in goat kids fed with artificial milk intended for calves]. Tijdschr Diergeneeskd 1992; 117:629-31. [PMID: 1440546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In a large commercial goat farm rickets-like symptoms were diagnosed in goat kids. The disease was probably caused by the synthetic milk which was freely available to the kids. The milk feed was for calves and had a calcium-phosphorus ratio of 0.83:1.
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Affiliation(s)
- D P Dercksen
- Gezondheidsdienst voor Dieren in Zuid- Nederland, Boxtel
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38
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Abstract
In a previous study, a genetic screening procedure was used to identify variants of bovine pancreatic trypsin inhibitor that can fold to an active conformation but that are inactivated much more rapidly than the wild-type protein in the presence of dithiothreitol (DTT). The mechanisms by which 30 of these DTT-sensitive variants are inactivated have now been investigated. Some of the amino acid replacements cause rapid inactivation in the presence of DTT because the three disulfides of the native protein are reduced up to 300-fold faster than for the wild-type protein, leading to complete unfolding. Other substitutions, however, do not greatly increase the rate of complete reduction and unfolding but lead to accumulation of an inactive two-disulfide species. There is a striking correlation between the locations of the DTT-sensitive amino acid replacements in the three-dimensional structure of the protein and the mechanisms by which the variants are inactivated. All of the substitutions that cause rapid unfolding are clustered at one end of the folded protein, in the vicinity of the two disulfides that are reduced most slowly during unfolding of the wild-type protein, while substitutions of the other class are all located at the other end of the protein, near the trypsin binding site. These results indicate that the kinetic stability of native bovine pancreatic trypsin inhibitor and its ability to function as a protease inhibitor are largely influenced by residues in two distinguishable regions of the folded protein.
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Affiliation(s)
- D P Goldenberg
- Department of Biology, University of Utah, Salt Lake City 84112
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39
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Abstract
Thirty-six normal subjects had to add two numbers ranging from 3 to 9 which were presented tachistoscopically. The two numbers were displayed either unilaterally to the left or right visual field, or bilaterally with one number to the left and one to the right visual field. They were represented as two word names, two dot clusters, or two bargraphs, or the two numbers were represented inconsistently in two different of these representations. The results showed that bilateral processing of a word and a bargraph was performed without visible interactions, and the hemispheres performed independently. When the display included a dot cluster, however, its processing (sequential vs. holistic) appeared to depend on the type of stimulus processed by the contralateral hemisphere, indicating strong interhemispheric interactions.
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40
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Berger JM, Jackson PJ, Robinson NJ, Lujan LD, Delhaize E. Precursor-product relationships of Poly(γ-glutamylcysteinyl)glycine biosynthesis in Datura innoxia. Plant Cell Rep 1989; 7:632-635. [PMID: 24240448 DOI: 10.1007/bf00272047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/1988] [Revised: 12/08/1988] [Indexed: 06/02/2023]
Abstract
Suspension cultures of Datura innoxia cells were pulse-labeled with [(35)S]cysteine, then exposed to Cd to determine whether there is a direct precursor-product relationship amongst the different forms of the Cd-induced polypeptides, poly(γ-glutamylcysteinyl)glycines [(γEC)nG, n=2 to 5]. Degradation of the polypeptides and possible regeneration of the [(35)S]-labeled glutathione and cysteine pools were also examined. After 2 h of exposure to [(35)S]cysteine, about 70% of the [(35)S]cysteine in the soluble fraction of the cell was incorporated into [(35)S]glutathione before exposure of the cells to Cd. One h after Cd exposure, most of the cellular [(35)S]glutathione was depleted and label was incorporated into (γEC)nG. Analysis of [(35)S](γEC)nG by reverse phase HPLC showed no direct precursor-product relationship between the synthesis of the shorter and longer chain forms. However, the rate of synthesis of the different polypeptides was linear for 32 h after Cd exposure. There was no evidence of degradation of [(35)S](γEC)nG nor was it excreted into the medium within this period. From these results it is suggested that in the presence of Cd, a large pool of (γEC)nG is unavailable for elongation to (γEC)n+1G.
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Affiliation(s)
- J M Berger
- Genetics Group, Mail Stop M886, Life Sciences Division, Los Alamos National Laboratory, 87545, Los Alamos, New Mexico, USA
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41
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Berger JM, Perret E, Zimmermann A. Role of interstimulus and stimulus-hemisphere compatibility in the process of interhemispheric integration. Percept Mot Skills 1988; 67:503-12. [PMID: 3217198 DOI: 10.2466/pms.1988.67.2.503] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Normal subjects had to name German compound nouns which were presented tachistoscopically. The compound nouns were displayed either unilaterally to the left or right visual field, or bilaterally with one element to the left and one to the right visual field. A distinction was made between the bilateral conditions as to whether the representation of the elements, printed and/or pictorial, included a high or low interstimulus and a high or low stimulus-hemisphere compatibility. Analysis indicated firstly a superiority of the left hemisphere for the naming of compound nouns in mixed print and pictorial representation. Secondly, the performance in the bilateral conditions was moderated by stimulus-hemisphere compatibility. In the process of interhemispheric integration stimulus-hemisphere compatibility proved more crucial than interstimulus compatibility. Analyses of errors further illustrated hemispheric behaviour.
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42
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Abstract
Subjects had to judge the semantic relation between two tachistoscopically presented German adjectives. In Exp. I, the two words were projected simultaneously, either both to the left visual field (i.e. to the right hemisphere, LVF-RH), or both to the right visual field (i.e. to the left hemisphere, RVF-LH), or one word to each visual field (i.e. to both hemispheres, EVF-BH). The results yielded a significantly higher performance in the condition EVF-BH than in the two unilateral conditions, without a significant difference between the latter two conditions. In Exp. II, the two words were shown successively. With bilateral presentation, a distinction was made as to whether the left visual field (EVF-BH-L) or the right visual field (EVF-BH-R) was stimulated first. The significantly highest performance was shown in conditions RVF-LH and EVF-BH-R compared with the condition EVF-BH-L, and the significantly poorest performance in the condition LVF-RH compared with the condition EVF-BH-L. The results provide evidence for (1) an intrahemispheric interference with simultaneous unilateral presentation, (2) a cooperative interhemispheric interaction with simultaneous bilateral presentation, and (3) an interhemispheric priming effect with successive bilateral presentation when the left hemisphere was stimulated first.
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Affiliation(s)
- J M Berger
- Department of Neurology, University Hospital, Zurich, Switzerland
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43
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Berger JM, Perret E. Fixation accuracy and perceptual asymmetry for consonants. Percept Mot Skills 1988; 66:569-70. [PMID: 3399335 DOI: 10.2466/pms.1988.66.2.569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Fixation accuracy was related to perception of laterally presented consonants. Small left-eye fixation inaccuracy influenced perceptual performance of 8 men and 8 women.
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Affiliation(s)
- J M Berger
- Swiss National Epilepsy Center, Zurich, Switzerland
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44
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Abstract
Normal subjects had to name German compound nouns which were presented tachistoscopically. The compound nouns were displayed either unilaterally to the left or right visual field or bilaterally with one element to each visual field. In the bilateral condition a distinction was made as to whether familiar or unfamiliar arrangement of the elements was used. Representation in print was compared with pictorial representation of the compound nouns. A right visual-field superiority was observed with printed representation, but no laterality effects with pictorial representation. Bilateral processing was superior to unilateral processing. Within the bilateral conditions, the familiar arrangement of the elements yielded a significantly better performance than unfamiliar arrangement. This difference can be explained by reading habits and/or by different styles of interhemispheric integration.
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45
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Berger JM, Ontell R. Intrathecal morphine in conjunction with a combined spinal and general anesthetic in a patient with multiple sclerosis. Anesthesiology 1987; 66:400-2. [PMID: 3826700 DOI: 10.1097/00000542-198703000-00025] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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46
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Berger JM, Perret E. A pronounced cognitive style improves interhemispheric integration: by hemispheric differentiation or by hemispheric similarity? Percept Mot Skills 1986; 63:947-54. [PMID: 3808876 DOI: 10.2466/pms.1986.63.2.947] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Under conditions of tachistoscopic stimulation normal subjects were presented visuospatial stimulus pairs which had to be integrated interhemispherically. The presence of a pronounced cognitive style improves the interhemispheric integration of this type of information. Two interpretations are discussed. The first explains the observed improvement with a qualitative division of labour, with one highly specialized and one just transmitting hemisphere, i.e., with hemispheric differentiation. The second emphasizes the relatively high capacity of the "subordinate" hemisphere in information processing, i.e., hemispheric similarity.
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47
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Abstract
Normal subjects were asked to estimate the total surface of two black spots presented tachistoscopically, either both to the right or both to the left visual field, or bilaterally to either visual field. Performance was highest with unilateral left visual field presentation and lowest with bilateral presentation of the spots. Interhemispheric integration varied with the quantitative relation between the stimuli in the left and right visual fields. Errors may be due in part to an insufficient cooperation of the left hemisphere and/or to an ignorance of the right hemisphere and/or to an unreliable transfer by the cerebral commissures.
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48
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Abstract
A case of bronchospasm during general anesthesia is presented in which atropine appeared to reverse bronchoconstriction, after high halothane concentrations, intratracheal lidocaine, and isoproterenol i.v. had all proved ineffective. This case illustrates a rational approach to the treatment of bronchospasm during anesthesia, based on determination of the most likely site of origin of bronchoconstriction within the tracheobronchial tree.
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49
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50
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Abstract
Cancer today presents patients and their families with an on-going series of crises. A drop-in, open ended, professionally-run support group for cancer patients and their families is described as a means of crisis intervention for the mobilization and promotion of adaptive responses and movement away from maladaptive responses to the stresses of cancer. This model is important because it can be easily generalized. As oncology units develop throughout the country in community-hospital settings, there must be concurrent development of psychosocial support systems.
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