Biochemistry, Biophysics, and Structural Biology Commons^™

An N-Terminal, 830 Residues Intrinsically Disordered Region Of The Cytoskeleton-Regulatory Protein Supervillin Contains Myosin Ii- And F-Actin-Binding Sites, Stanislav Fedechkin, Jacob Brockerman, Elizabeth Luna, Michail Lobanov, Oxana Galzitskaya, Serge Smirnov

Elizabeth J. Luna

Supervillin, the largest member of the villin/gelsolin family, is a cytoskeleton regulating, peripheral membrane protein. Supervillin increases cell motility and promotes invasive activity in tumors. Major cytoskeletal interactors, including filamentous actin and myosin II, bind within the unique supervillin amino terminus, amino acids 1-830. The structural features of this key region of the supervillin polypeptide are unknown. Here, we utilize circular dichroism and bioinformatics sequence analysis to demonstrate that the N-terminal part of supervillin forms an extended intrinsically disordered region (IDR). Our combined data indicate that the N-terminus of human and bovine supervillin sequences (positions 1-830) represents an IDR, which …

Psychosine, The Cytotoxic Sphingolipid That Accumulates In Globoid Cell Leukodystrophy, Alters Membrane Architecture, Jacqueline A. Hawkins-Salsbury, Archana R. Parameswar, Xuntian Jiang, Paul H. Schlesinger, Ernesto Bongarzone, Daniel S. Ory, Alexei V. Demchenko, Mark S. Sands

Alexei Demchenko

Inhibition Of Bacillus Cereus Growth By Bacteriocin Producing Bacillus Subtilis Isolated From Fermented Baobab Seeds (Maari) Is Substrate Dependent, Donatien Kaboré, Dennis S. Nielsen, Hagrétoui Sawadogo-Lingan, Bréhima Diawara, Mamoudou H. Dicko Prof., Mogens Jakobsen, Line Thorsen

Pr. Mamoudou H. DICKO, PhD

Quantitative Non-Isotopic Nitrocellulose Filter Binding Assays: Bacterial Mnsod-Dna Interactions, Joshua D. Czerwinski, David P. Mascotti

David P. Mascotti

No abstract provided.

Thermal And Sodium Dodecylsulfate Induced Transitions Of Streptavidin, Mark J. Waner, Irina Navrotskaya, Amanda Bain, Edward D. Oldham, David P. Mascotti

Mark J. Waner

The strong specific binding of streptavidin (SA) to biotin is utilized in numerous biotechnological applications. The SA tetramer is also known to exhibit significant stability, even in the presence of sodium dodecylsulfate (SDS). Despite its importance, relatively little is known about the nature of the thermal denaturation pathway for SA. This work uses a homogeneous SA preparation to expand on the data of previous literature reports, leading to the proposal of a model for temperature induced structural changes in SA. Temperature dependent data were obtained by SDS and native polyacrylamide gel electrophoresis (PAGE), differential scanning calorimetry (DSC), and fluorescence and …

The Effect Of Oxidant And The Non-Oxidant Alteration Of Cellular Thiol Concentration On The Formation Of Protein Mixed-Disulfides In Hek 293 Cells, Jasen Lee Gilge, Michael Fisher, Yuh-Cherng Chai

Yuh-Cherng Chai

Cellular molecules possess various mechanisms in responding to oxidant stress. In terms of protein responses, protein S-glutathionylation is a unique post-translational modification of protein reactive cysteines forming disulfides with glutathione molecules. This modification has been proposed to play roles in antioxidant, regulatory and signaling in cells under oxidant stress. Recently, the increased level of protein S-glutathionylation has been linked with the development of diseases. In this report, specific S-glutathionylated proteins were demonstrated in human embryonic kidney 293 cells treated with two different oxidative reagents: diamide and hydrogen peroxide. Diamide is a chemical oxidizing agent whereas hydrogen peroxide is a physiological …

Transmembrane Serine Mutations Reduce The Minimum Pore Diameter Of Channelrhodopsin-2, Robert Dempski, Ryan Richards

Robert E. Dempski

Channelrhodopsin-2 (ChR2) is a microbial-type rhodopsin that, together with channelrhodopsin-1, mediates phototactic behavior in the green algae Chlamydomonas reinhardtii. Like all other microbial-type rhodopsins, ChR2 has seven transmembrane domains with the chromophore all-trans retinal bound to a single lysine residue. However, unlike other microbial-type rhodopsins, ChR2 functions as a non-selective cation channel and not an ion pump. A sequence alignment of ChR2 with the proton pump bacteriorhodopsin (bR) reveals that ChR2 lacks specific motifs within the transmembrane domains that facilitate non-covalent interactions and contribute to protein stability.

Structural Adaptations Of Proteins To Different Biological Membranes, Prof. Stephanie Tristram-Nagle, Irina Pogozheva, Harold Mosberg, Andrei Lomize

Prof. Stephanie Tristram-Nagle Ph.D.

To gain insight into adaptations of proteins to their membranes, intrinsic hydrophobic thicknesses, distributions of different chemical groups and profiles of hydrogen-bonding capacities (α and β) and the dipolarity/ polarizability parameter (π*) were calculated for lipid-facing surfaces of 460 integral α-helical, β-barrel and peripheral proteins from eight types of biomembranes. For comparison, polarity profiles were also calculated for ten artificial lipid bilayers that have been previously studied by neutron and X-ray scattering. Estimated hydrophobic thicknesses are 30–31 Å for proteins from endoplasmic reticulum, thylakoid, and various bacterial plasma membranes, but differ for proteins from outer bacterial, inner mitochondrial and eukaryotic …

Periplasmic Response Upon Disruption Of Transmembrane Cu Transport In Pseudomonas Aeruginosa., José Argüello, Daniel Raimunda, Teresita Padilla-Benavides, Stefan Vogt, Sylvain Boutigny, Kaleigh Tomkinson, Lydia Finney

José M. Argüello

Pseudomonas aeruginosa, an opportunistic pathogen, has two transmembrane Cu(+) transport ATPases, CopA1 and CopA2. Both proteins export cytoplasmic Cu(+) into the periplasm and mutation of either gene leads to attenuation of virulence. CopA1 is required for maintaining cytoplasmic copper levels, while CopA2 provides copper for cytochrome c oxidase assembly. We hypothesized that transported Cu(+) ions would be directed to their destination via specific periplasmic partners and disruption of transport should affect the periplasmic copper homeostasis. Supporting this, mutation of either ATPase gene led to large increments in periplasmic cuproprotein levels. Toward identifying the proteins participating in this cellular response the …

Mechanisms Of Copper Homeostasis In Bacteria, José Argüello, Daniel Raimunda, Teresita Padilla-Benavides

José M. Argüello

Copper is an important micronutrient required as a redox co-factor in the catalytic centers of enzymes. However, free copper is a potential hazard because of its high chemical reactivity. Consequently, organisms exert a tight control on Cu(+) transport (entry-exit) and traffic through different compartments, ensuring the homeostasis required for cuproprotein synthesis and prevention of toxic effects. Recent studies based on biochemical, bioinformatics, and metalloproteomics approaches, reveal a highly regulated system of transcriptional regulators, soluble chaperones, membrane transporters, and target cuproproteins distributed in the various bacterial compartments. As a result, new questions have emerged regarding the diversity and apparent redundancies of …

Sinorhizobium Meliloti Nia Is A P(1b-5)-Atpase Expressed In The Nodule During Plant Symbiosis And Is Involved In Ni And Fe Transport., José Argüello, Eliza Zielazinski, Manuel Gonzalez-Guerrero, Poorna Subramanian, Timothy Stemmler, Amy Rosenzweig

José M. Argüello

The P1B-ATPases are a ubiquitous family of metal transporters. These transporters are classified into subfamilies on the basis of substrate specificity, which is conferred by conserved amino acids in the last three transmembrane domains. Five subfamilies have been identified to date, and representative members of four (P1B-1 to P1B-4) have been studied. The fifth family (P1B-5), of which some members contain a C-terminal hemerythrin (Hr) domain, is less well characterized. The S. meliloti Sma1163 gene encodes for a P1B-5-ATPase, denoted Nia (Nickel-iron ATPase), that is induced by exogenous Fe(2+) and Ni(2+). The nia mutant accumulates nickel and iron, suggesting a …

Structure And Dynamics Of A Primordial Catalytic Fold Generated By In Vitro Evolution, Fa-An Chao, Aleardo Morelli, John C. Haugner Iii, Lewis Churchfield, Lei Shi, Larry R. Masterson, Ritimukta Sarangi, Gianluigi Veglia, Burckhard Seelig

Larry Masterson

Rab5 Function In Breast Cancer Cells, Nicole Porther, M Alejandro Barbieri

Nicole Porther

Membrane Structure Correlates To Function Of Llp2 On The Cytoplasmic Tail Of Hiv-1 Gp41 Protein, Alexander Boscia, Zachary Benamram, Jonathan Michel, Michael Jablin, Jonathan D. Steckbeck, Ronald C. Montelaro, John F. Nagle, Prof. Stephanie Tristram-Nagle Ph.D.

Prof. Stephanie Tristram-Nagle Ph.D.

Mutation studies previously showed that the lentivirus lytic peptide (LLP2) sequence of the cytoplasmic C-terminal tail of the HIV-1 gp41 envelope protein inhibited viral-initiated T-cell death and T-cell syncytium formation, at which time in the HIV life cycle the gp41 protein is embedded in the T-cell membrane. In striking contrast, the mutants did not affect virion infectivity, during which time the gp41 protein is embedded in the HIV envelope membrane. To examine the role of LLP2/membrane interactions, we applied synchrotron X-radiation to determine structure of hydrated membranes. We focused on WT LLP2 peptide (þlus three charge) and MX2 mutant (negative …

Ahsg-Fetuin Blocks The Metabolic Arm Of Insulin Action Through Its Interaction With The 95-Kd Beta-Subunit Of The Insulin Receptor, Anton Scott Goustin

Anton Scott Goustin

We previously have shown that Ahsg, a liver glycoprotein, inhibits insulin receptor (InsR) tyrosine kinase (TK) activity and the ERK1/2 mitogenic signaling arm of insulin signaling. Here we show that Ahsg blocks insulin-stimulated GLUT4 translocation and Akt activation in intact cells (mouse myoblasts). Furthermore, Ahsg inhibits InsR autophosphorylation of highly-purified insulin holoreceptors in a cell-free, ATP-dependent system,with an IC50within the range of single-chain Ahsg concentrations in human serum. Binding of 125I-insulin to living cells overexpressing the InsR shows a dissociation constant (KD) of 250 pM, unaltered in the presence of 300 nMAhsg. Amutant InsR cDNA encoding the signal peptide, the …

Conditional Knockdown Of Dna Methyltransferase-1 (Dnmt1) Reveals A Key Role Of Retinal Pigment Epithelium In Mammalian Photoreceptor Differentiation, I. O. Nasonkin, S. L. Merbs, K. Lazo, V. F. Oliver, M. Brooks, K. Patel, Raymond Enke, J. Nellissery, M. Jamrich, Y. Z. Le, K. Bharti, R. N. Fariss, R. A. Rachel, D. J. Zack, E. Rodriguez-Boulan, A. Swaroop

Ray Enke Ph.D.

No abstract provided.

Determination Of Dosage Compensation Of The Mammalian X Chromosome By Rna-Seq Is Dependent On Analytical Approach, Nathaniel K. Jue, Michael B. Murphy, Seth D. Kasowitz, Sohaib M. Qureshi, Craig J. Obergfell, Sahar Elsisi, Robert J. Foley, Rachel J. O’Neill, Michael J. O’Neill

Nathaniel Jue