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Full-Text Articles in Physical Sciences and Mathematics

Structural Evidence For Consecutive Hel308-Like Modules In The Spliceosomal Atpase Brr2, L. Zhang, T. Xu, Corina Maeder, L.-O. Bud, J. Shanks, J. Nix, C. Guthrie, J. A. Pleiss, R. Zhao Jul 2009

Structural Evidence For Consecutive Hel308-Like Modules In The Spliceosomal Atpase Brr2, L. Zhang, T. Xu, Corina Maeder, L.-O. Bud, J. Shanks, J. Nix, C. Guthrie, J. A. Pleiss, R. Zhao

Chemistry Faculty Research

Brr2 is a DExD/H-box helicase responsible for U4/U6 unwinding during spliceosomal activation. Brr2 contains two helicase-like domains, each of which is followed by a Sec63 domain with unknown function. We determined the crystal structure of the second Sec63 domain, which unexpectedly resembles domains 4 and 5 of DNA helicase Hel308. This, together with sequence similarities between Brr2's helicase-like domains and domains 1-3 of Hel308, led us to hypothesize that Brr2 contains two consecutive Hel308-like modules (Hel308-I and Hel308-II). Our structural model and mutagenesis data suggest that Brr2 shares a similar helicase mechanism with Hel308. We demonstrate that Hel308-II interacts with …


Adsorption Of Co On Supported Gold Nanoparticle Catalysts: A Comparative Study, Heather Hartshorn, Christopher J. Pursell, Bert D. Chandler Apr 2009

Adsorption Of Co On Supported Gold Nanoparticle Catalysts: A Comparative Study, Heather Hartshorn, Christopher J. Pursell, Bert D. Chandler

Chemistry Faculty Research

The adsorption of CO on three different gold nanoparticle catalysts supported on high surface area TiO2 was studied using infrared transmission spectroscopy at room temperature and CO pressures typically used in CO oxidation reactions. The three, real-world catalysts were Au catalysts synthesized in our laboratory from thiol monolayer protected clusters (MPCs) and two commercial catalysts from the World Gold Council (WGC and AuTEK). Within experimental reproducibility, the adsorption data for the three catalysts are indistinguishable. While showing approximately Langmuir behavior, the adsorption data also show coverage dependence, as others have observed for many catalyst systems. Two approaches were used …


Multivalent Recognition Of Peptides By Modular Self-Assembled Receptors, Joseph J. Reczek, Aimee A. Kennedy, Brian T. Halbert, Adam R. Urbach Feb 2009

Multivalent Recognition Of Peptides By Modular Self-Assembled Receptors, Joseph J. Reczek, Aimee A. Kennedy, Brian T. Halbert, Adam R. Urbach

Chemistry Faculty Research

Developing nontraditional approaches to the synthesis and characterization of multivalent compounds is critical to our efforts to study and interface with biological systems and to build new noncovalent materials. This paper demonstrates a biomimetic approach to the construction of discrete, modular, multivalent receptors via molecular self-assembly in aqueous solution. Scaffolds presenting 1−3 viologen groups recruit a respective 1−3 copies of the synthetic host, cucurbit[8]uril, in a noncooperative manner and with a consistent equilibrium association constant (Ka) value of 2 × 106 M−1 per binding site. The assembled mono-, di-, and trivalent receptors bind to their …


Patterning High Surface Area Silica With Lysozyme: Adsorption Kinetics, Fluorescence Quenching, And Protein Readsorption Studies To Evaluate The Templated Surface, Rachel M. Greer, Brittni A. Scruggs, R Alan May, Bert D. Chandler Jan 2009

Patterning High Surface Area Silica With Lysozyme: Adsorption Kinetics, Fluorescence Quenching, And Protein Readsorption Studies To Evaluate The Templated Surface, Rachel M. Greer, Brittni A. Scruggs, R Alan May, Bert D. Chandler

Chemistry Faculty Research

A method was developed for using an inexpensive and widely available protein, hen egg white lysozyme, as a patterning agent for commercial high surface area silicas. The basic patterning methodology involved spontaneous adsorption of the protein from aqueous solution, alkylation of the uncovered surface with an alkylsiloxane, and protein desorption in a slightly alkaline solution of morpholine. Adsorption kinetic studies using Bradford assays assisted in determining protein deposition conditions. These studies were generally consistent with results on more planar silica surfaces and indicated that the protein quickly and strongly adsorbs along its long axis at low surface coverages. A modified …


Atp-Dependent Unwinding Of U4/U6 Snrnas By The Brr2 Helicase Requires The C Terminus Of Prp8, Corina Maeder, A. K. Kutach, C. Guthrie Jan 2009

Atp-Dependent Unwinding Of U4/U6 Snrnas By The Brr2 Helicase Requires The C Terminus Of Prp8, Corina Maeder, A. K. Kutach, C. Guthrie

Chemistry Faculty Research

The spliceosome is a highly dynamic machine requiring multiple RNA-dependent ATPases of the DExD/H-box family. A fundamental unanswered question is how their activities are regulated. Brr2 function is necessary for unwinding the U4/U6 duplex, a step essential for catalytic activation of the spliceosome. Here we show that Brr2-dependent dissociation of U4/U6 snRNAs in vitro is activated by a fragment from the C terminus of the U5 snRNP protein Prp8. In contrast to its helicase-stimulating activity, this fragment inhibits Brr2 U4/U6-dependent ATPase activity. Notably, U4/U6 unwinding activity is not stimulated by fragments carrying alleles of prp8 that in humans confers an …


Oligocarbonate Molecular Transporters: Oligomerization-Based Syntheses And Cell-Penetrating Studies, Christina B. Cooley, B. M. Trantow, F. Nederberg, M. K. Kiesewetter, J. L. Hedrick, R. M. Waymouth, P. A. Wender Jan 2009

Oligocarbonate Molecular Transporters: Oligomerization-Based Syntheses And Cell-Penetrating Studies, Christina B. Cooley, B. M. Trantow, F. Nederberg, M. K. Kiesewetter, J. L. Hedrick, R. M. Waymouth, P. A. Wender

Chemistry Faculty Research

A new family of guanidinium-rich molecular transporters featuring a novel oligocarbonate backbone with 1,7-side chain spacing is described. Conjugates can be rapidly assembled irrespective of length in a one-step oligomerization strategy that can proceed with concomitant introduction of probes (or by analogy drugs). The new transporters exhibit excellent cellular entry as determined by flow cytometry and fluorescence microscopy, and the functionality of their drug delivery capabilities was confirmed by the delivery of the bioluminescent small molecule probe luciferin and turnover by its intracellular target enzyme.