scholarly journals Characterization of a Viral Phosphoprotein Binding Site on the Surface of the Respiratory Syncytial Nucleoprotein

2012 ◽  
Vol 86 (16) ◽  
pp. 8375-8387 ◽  
Author(s):  
Marie Galloux ◽  
Bogdan Tarus ◽  
Ilfad Blazevic ◽  
Jenna Fix ◽  
Stéphane Duquerroy ◽  
...  
Keyword(s):  
Biochemical Characterization ◽  
Specific Interaction ◽  
Viral Rna ◽  
Site Directed Mutagenesis ◽  
Luciferase Reporter ◽  
Potential Candidate ◽  
Luciferase Reporter Gene ◽  
Interaction Domain ◽  
Rna Complex

The human respiratory syncytial virus (HRSV) genome is composed of a negative-sense single-stranded RNA that is tightly associated with the nucleoprotein (N). This ribonucleoprotein (RNP) complex is the template for replication and transcription by the viral RNA-dependent RNA polymerase. RNP recognition by the viral polymerase involves a specific interaction between the C-terminal domain of the phosphoprotein (P) (PCTD) and N. However, the P binding region on N remains to be identified. In this study, glutathioneS-transferase (GST) pulldown assays were used to identify the N-terminal core domain of HRSV N (NNTD) as a P binding domain. A biochemical characterization of the PCTDand molecular modeling of the NNTDallowed us to define four potential candidate pockets on N (pocket I [PI] to PIV) as hydrophobic sites surrounded by positively charged regions, which could constitute sites complementary to the PCTDinteraction domain. The role of selected amino acids in the recognition of the N-RNA complex by P was first screened for by site-directed mutagenesis using a polymerase activity assay, based on an HRSV minigenome containing a luciferase reporter gene. When changed to Ala, most of the residues of PI were found to be critical for viral RNA synthesis, with the R132A mutant having the strongest effect. These mutations also reduced or abolishedin vitroandin vivoP-N interactions, as determined by GST pulldown and immunoprecipitation experiments. The pocket formed by these residues is critical for P binding to the N-RNA complex, is specific for pneumovirus N proteins, and is clearly distinct from the P binding sites identified so far for other nonsegmented negative-strand viruses.

Characterization of cis-elements required for osmotic response of rat Na+/H+exchanger-2 (NHE-2) gene

1999 ◽  
Vol 277 (4) ◽  
pp. R1112-R1119 ◽  
Author(s):  
Liqun Bai ◽  
James F. Collins ◽  
Yunhua L. Muller ◽  
Hua Xu ◽  
Pawel R. Kiela ◽  
...  
Keyword(s):  
Transcriptional Regulation ◽  
Dna Sequences ◽  
Collecting Duct ◽  
Specific Interaction ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Response Elements ◽  
Osmotic Response ◽  
Responsive Element

The Na+/H+exchanger ( NHE-2) has been implicated in osmoregulation in the kidney, because it transports Na+ across the cell membrane and efficiently alters intracellular osmolarity. On hyperosmotic stress, NHE-2 mRNA increases in abundance in mouse inner medullary collecting duct (mIMCD-3) cells, suggesting possible transcriptional regulation. To investigate the molecular mechanism of potential transcriptional regulation of NHE-2 by hyperosmolarity, we have functionally characterized the 5′-flanking region of the gene in mIMCD-3 cells. Transient transfection of luciferase reporter gene constructs revealed a novel cis-acting element, which we call OsmoE (osmotic-responsive element, bp −808 to −791, GGGCCAGTTGGCGCTGGG), and a TonE-like element (tonicity-responsive element, bp −1201 to −1189, GCTGGAAAACCGA), which together are shown to be responsible for hyperosmotic induction of the NHE-2gene. Electrophoretic mobility shift assays suggest that different DNA-protein interactions occur between these two osmotic response elements. However, both DNA sequences were shown to specifically bind nuclear proteins that dramatically increase in abundance under hyperosmotic conditions. Isolation of trans-acting factors and characterization of their specific interaction with these osmotic response elements will further elucidate the transcriptional mechanisms controlling NHE-2 gene expression under hyperosmolar conditions.

scholarly journals Xiao Yao San against Corticosterone-Induced Stress Injury via Upregulating Glucocorticoid Receptor Reaction Element Transcriptional Activity

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Guoping Cao ◽  
Shenglan Gong ◽  
Fengxue Zhang ◽  
Wenjun Fu
Keyword(s):  
Hippocampal Neurons ◽  
Transcriptional Activity ◽  
Nuclear Translocation ◽  
Luciferase Reporter ◽  
Potential Candidate ◽  
Luciferase Reporter Gene ◽  
Mobility Shift ◽  
Stress Injury ◽  
Induced Stress

Previous studies have revealed that uncontrollable stress can impair the synaptic plasticity and firing property of hippocampal neurons, which influenced various hippocampal-dependent tasks including memory, cognition, behavior, and mood. In this work, we had investigated the effects and mechanisms of the Chinese herbal medicine Xiao Yao San (XYS) against corticosterone-induced stress injury in primary hippocampal neurons (PHN) cells. We found that XYS and RU38486 could increase cell viabilities and decrease cell apoptosis by MTT, immunofluorescence, and flow cytometry assays. In addition, we observed that XYS notably inhibited the nuclear translocation of GR and upregulated the mRNA and protein expressions levels of Caveolin-1, GR, BDNF, TrkB, and FKBP4. However, XYS downregulated the FKBP51 expressions. Furthermore, the results of the electrophoretic mobility shift assay (EMSA) and double luciferase reporter gene detection indicated that FKBP4 promotes the transcriptional activity of GR reaction element (GRE) by binding with GR, and FKBP51 processed the opposite action. Thein vivoexperiment also proved the functions of XYS. These results suggested that XYS showed an efficient neuroprotection against corticosterone-induced stress injury in PHN cells by upregulating GRE transcriptional activity, which should be developed as a potential candidate for treating stress injury in the future.

scholarly journals Biochemical Characterization of Laboratory Mutants of Extended-Spectrum β-Lactamase TEM-60

2004 ◽  
Vol 48 (9) ◽  
pp. 3579-3582 ◽  
Author(s):  
Bibiana Caporale ◽  
Nicola Franceschini ◽  
Mariagrazia Perilli ◽  
Bernardetta Segatore ◽  
Gian Maria Rossolini ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Kinetic Parameters ◽  
Biochemical Characterization ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Extended Spectrum

ABSTRACT Three mutants of the extended-spectrum β-lactamase TEM-60, the P51L, K104E, and S164R mutants, were constructed by site-directed mutagenesis. The kinetic parameters of the mutated enzymes and interactions of inhibitors were significantly different from those of TEM-60, revealing that the L51P mutation plays an important role in enzyme activity and stability in the TEM-60 background.

scholarly journals Genetic and Biochemical Characterization of Salmonella enterica Serovar Typhi Deoxyribokinase

2000 ◽  
Vol 182 (4) ◽  
pp. 869-873 ◽  
Author(s):  
Lise Tourneux ◽  
Nadia Bucurenci ◽  
Cosmin Saveanu ◽  
Pierre Alexandre Kaminski ◽  
Madeleine Bouzon ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Biochemical Characterization ◽  
Site Directed Mutagenesis ◽  
Gene Encoding ◽  
E Coli ◽  
Salmonella Enterica Serovar Typhi ◽  
Acid Protein ◽  
Serovar Typhimurium ◽  
Amino Acid Protein

ABSTRACT We identified in the genome of Salmonella entericaserovar Typhi the gene encoding deoxyribokinase, deoK. Two other genes, vicinal to deoK, were determined to encode the putative deoxyribose transporter (deoP) and a repressor protein (deoQ). This locus, located between theuhpA and ilvN genes, is absent inEscherichia coli. The deoK gene inserted on a plasmid provides a selectable marker in E. coli for growth on deoxyribose-containing medium. Deoxyribokinase is a 306-amino-acid protein which exhibits about 35% identity with ribokinase from serovar Typhi, S. enterica serovar Typhimurium, or E. coli. The catalytic properties of the recombinant deoxyribokinase overproduced in E. colicorrespond to those previously described for the enzyme isolated from serovar Typhimurium. From a sequence comparison between serovar Typhi deoxyribokinase and E. coliribokinase, whose crystal structure was recently solved, we deduced that a key residue differentiating ribose and deoxyribose is Met10, which in ribokinase is replaced by Asn14. Replacement by site-directed mutagenesis of Met10 with Asn decreased theV max of deoxyribokinase by a factor of 2.5 and increased the K m for deoxyribose by a factor of 70, compared to the parent enzyme.

Creation and Characterization of a Doxycycline-Inducible Mouse Model of Thyroid-Targeted RET/PTC1 Oncogene and Luciferase Reporter Gene Coexpression

Thyroid ◽  
2007 ◽  
Vol 17 (12) ◽  
pp. 1181-1188 ◽  
Author(s):  
Katherine A.B. Knostman ◽  
Anjli Venkateswaran ◽  
Bevin Zimmerman ◽  
Charles C. Capen ◽  
Sissy M. Jhiang
Keyword(s):  
Mouse Model ◽  
Reporter Gene ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Gene Coexpression

scholarly journals Identification of Residues Important for the Activity ofHaloferax volcaniiAglD, a Component of the Archaeal N-Glycosylation Pathway

Archaea ◽  
2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Lina Kaminski ◽  
Jerry Eichler
Keyword(s):  
Biochemical Characterization ◽  
Haloferax Volcanii ◽  
Site Directed Mutagenesis ◽  
Directed Mutagenesis ◽  
Amino Acid Residues ◽  
Natural Substrate ◽  
Identify Amino Acid ◽  
Glycosylation Pathway

InHaloferax volcanii, AglD adds the final hexose to the N-linked pentasaccharide decorating the S-layer glycoprotein. Not knowing the natural substrate of the glycosyltransferase, together with the challenge of designing assays compatible with hypersalinity, has frustrated efforts at biochemical characterization of AglD activity. To circumvent these obstacles, an in vivo assay designed to identify amino acid residues important for AglD activity is described. In the assay, restoration of AglD function in anHfx. volcanii aglDdeletion strain transformed to express plasmid-encoded versions of AglD, generated through site-directed mutagenesis at positions encoding residues conserved in archaeal homologues of AglD, is reflected in the behavior of a readily detectable reporter of N-glycosylation. As such Asp110 and Asp112 were designated as elements of the DXD motif of AglD, a motif that interacts with metal cations associated with nucleotide-activated sugar donors, while Asp201 was predicted to be the catalytic base of the enzyme.

scholarly journals Purification and Characterization of NafY (Apodinitrogenase γ Subunit) fromAzotobacter vinelandii

2004 ◽  
Vol 279 (19) ◽  
pp. 19739-19746 ◽  
Author(s):  
Luis M. Rubio ◽  
Steven W. Singer ◽  
Paul W. Ludden
Keyword(s):  
Biochemical Characterization ◽  
Azotobacter Vinelandii ◽  
Site Directed Mutagenesis ◽  
Cofactor Binding ◽  
Unknown Structure ◽  
Additional Protein ◽  
Epr Signal ◽  
Iron Molybdenum Cofactor ◽  
Very High

The formation of an active dinitrogenase requires the synthesis and the insertion of the iron-molybdenum cofactor (FeMo-co) into a presynthesized apodinitrogenase. InAzotobacter vinelandii, NafY (also known as γ protein) has been proposed to be a FeMo-co insertase because of its ability to bind FeMo-co and apodinitrogenase. Here we report the purification and biochemical characterization of NafY and reach the following conclusions. First, NafY is a 26-kDa monomeric protein that binds one molecule of FeMo-co with very high affinity (Kd≈ 60 nm); second, the NafY-FeMo-co complex exhibits aS= 3/2 EPR signal with features similar to the signals for extracted FeMo-co and the M center of dinitrogenase; third, site-directed mutagenesis ofnafYindicates that the His121residue of NafY is involved in cofactor binding; and fourth, NafY binding to apodinitrogenase or to FeMo-co does not require the presence of any additional protein. In addition, we have obtained evidence that suggests the ability of NafY to bind NifB-co, an FeS cluster of unknown structure that is a biosynthetic precursor to FeMo-co.

scholarly journals Human TAFII130 Is a Coactivator for NFATp

2001 ◽  
Vol 21 (10) ◽  
pp. 3503-3513 ◽  
Author(s):  
Loree J. Kim ◽  
Anita G. Seto ◽  
Tuan N. Nguyen ◽  
James A. Goodrich
Keyword(s):  
Transcriptional Activation ◽  
Biochemical Characterization ◽  
Luciferase Reporter ◽  
Transcription System ◽  
Transcription In Vitro ◽  
Necessary And Sufficient ◽  
In Vitro Interaction ◽  
Tfiid Complex

ABSTRACT NFATp is one member of a family of transcriptional activators that regulate the expression of cytokine genes. To study mechanisms of NFATp transcriptional activation, we established a reconstituted transcription system consisting of human components that is responsive to activation by full-length NFATp. The TATA-associated factor (TAFII) subunits of the TFIID complex were required for NFATp-mediated activation in this transcription system, since TATA-binding protein (TBP) alone was insufficient in supporting activated transcription. In vitro interaction assays revealed that human TAFII130 (hTAFII130) and itsDrosophila melanogaster homolog dTAFII110 bound specifically and reproducibly to immobilized NFATp. Sequences contained in the C-terminal domain of NFATp (amino acids 688 to 921) were necessary and sufficient for hTAFII130 binding. A partial TFIID complex assembled from recombinant hTBP, hTAFII250, and hTAFII130 supported NFATp-activated transcription, demonstrating the ability of hTAFII130 to serve as a coactivator for NFATp in vitro. Overexpression of hTAFII130 in Cos-1 cells inhibited NFATp activation of a luciferase reporter. These studies demonstrate that hTAFII130 is a coactivator for NFATp and represent the first biochemical characterization of the mechanism of transcriptional activation by the NFAT family of activators.

Structure of mouse muskelin discoidin domain and biochemical characterization of its self-association

2014 ◽  
Vol 70 (11) ◽  
pp. 2863-2874 ◽  
Author(s):  
Kook-Han Kim ◽  
Seung Kon Hong ◽  
Kwang Yeon Hwang ◽  
Eunice EunKyeong Kim
Keyword(s):  
Crystal Structure ◽  
Cell Adhesion ◽  
Disulfide Bonds ◽  
Biochemical Characterization ◽  
Specific Interaction ◽  
Repeat Domain ◽  
Interdomain Interaction ◽  
Self Association ◽  
Cytoskeleton Dynamics

Muskelin is an intracellular kelch-repeat protein comprised of discoidin, LisH, CTLH and kelch-repeat domains. It is involved in cell adhesion and the regulation of cytoskeleton dynamics as well as being a component of a putative E3 ligase complex. Here, the first crystal structure of mouse muskelin discoidin domain (MK-DD) is reported at 1.55 Å resolution, which reveals a distorted eight-stranded β-barrel with two short α-helices at one end of the barrel. Interestingly, the N- and C-termini are not linked by the disulfide bonds found in other eukaryotic discoidin structures. A highly conserved MIND motif appears to be the determinant for MK-DD specific interaction together with the spike loops. Analysis of interdomain interaction shows that MK-DD binds the kelch-repeat domain directly and that this interaction depends on the presence of the LisH domain.

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