http://hdl.handle.net/10027/1235 Mon, 20 May 2013 12:23:39 GMT 2013-05-20T12:23:39Z http://hdl.handle.net/10027/8618 Polycistronic coexpression and nondenaturing purification of histone octamers Shim, Yoonjung; Duan, Ming-Rui; Chen, Xuejing; Smerdon, Michael J.; Min, Jung-Hyun Histone octamers are the basic building blocks of chromatin and are platforms for diverse genetic mechanisms. We report a simple method for preparing recombinant histone octamers by overexpressing all four histones from a single polycistronic vector followed by standard chromatography under native conditions. This approach reduces the time needed for the octamer preparation to a single day and should be applicable to making a variety of unmodified and modified histone octamers. NOTICE: this is the author’s version of a work that was accepted for publication in Analytical Biochemistry. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Analytical Biochemistry, [427 (2), (2012 Aug 15)] DOI: 10.1016/j.ab.2012.05.006 Wed, 15 Aug 2012 05:00:00 GMT http://hdl.handle.net/10027/8618 2012-08-15T05:00:00Z http://hdl.handle.net/10027/8558 Self-standing Nanoparticle Membranes and Capsules Chan, Henry; Král, Petr We perform coarse-grained molecular dynamics simulations of self-standing nanoparticle membranes observed in recent experiments (Nat. Mater. 6, 656 (2007)). In order to make our simulations feasible, we model 2 − 3 times smaller gold nanoparticles (core radius of rcore ≈ 0.8 nm) covered with alkanethiol ligands (length of lligand ≈ 0.5−2.6 nm). We study the structure, stability, and mechanical properties of these membranes and show that these characteristics are controlled by the ratio of RLC = lligand/rcore. For RLC ≈ 0.6, the ligated nanoparticles form well ordered mono- layers with hexagonal packing, in agreement with the experiments (RLC ≈ 0.44). For RLC ≈ 1.6, the nanoparticles form less organized multilayers, which are more stable and flexible. We show that these membranes could potentially form stable capsules for molecular storage and delivery. The original version is available through Royal Society of Chemistry at DOI: 10.1039/c0nr00912a Fri, 01 Apr 2011 05:00:00 GMT http://hdl.handle.net/10027/8558 2011-04-01T05:00:00Z http://hdl.handle.net/10027/8547 Configuration of membrane-bound proteins by x-ray reflectivity Chen, Chiu-Hao; Ma´lkova, Sa´rka; Cho, Wonhwa; Schlossman, Mark L. In this presentation we review our recent work using x-ray reflectivity to determine the configuration of membrane-bound proteins. The reflectivity data is analyzed in terms of the known crystallographic structure of proteins and a slab model representing the lipid layer to yield an electron density profile of the lipid/protein system. Our recent modified analysis methodology for the lipid/protein system is concisely described in this report. In addition, some results of the configuration of the membrane-bound proteins cPLA2a-C2, p40phox-PX, and PKCa-C2 are highlighted. Copyright 2011 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Chen, C. H., Malkova, S., Cho, W., & Schlossman, M. L. 2011. Configuration of membrane-bound proteins by x-ray reflectivity. Journal of Applied Physics, 110(10). and may be found at http://jap.aip.org/resource/1/japiau/v110/i10/p102215_s1. DOI: 10.1063/1.3661985 Mon, 01 Nov 2010 05:00:00 GMT http://hdl.handle.net/10027/8547 2010-11-01T05:00:00Z http://hdl.handle.net/10027/8410 Comparing Vacuum and Extreme Ultraviolet Radiation for Postionization of Laser Desorbed Neutrals from Bacterial Biofilms and Organic Fullerenes Gasper, G. L.; Takahashi, L.K.; Zhou, J.; Ahmed, M.; Moore, J.F.; Hanley, L. Vacuum and extreme ultraviolet radiation from 8 - 24 eV generated at a synchrotron was used to postionize laser desorbed neutrals of antibiotic-treated biofilms and a modified fullerene using laser desorption postionization mass spectrometry (LDPI-MS). Results show detection of the parent ion, various fragments, and extracellular material from biofilms using LDPI-MS with both vacuum and extreme ultraviolet photons. Parent ions were observed for both cases, but extreme ultraviolet photons (16 - 24 eV) induced more fragmentation than vacuum ultraviolet (8 - 14 eV) photons. NOTICE: this is the author’s version of a work that was accepted for publication in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, [Vol 649, Issue 1, 2011 Sep 1] DOI: 10.1016/j.nima.2010.12.024. The original publication is available at www.elsevier.com. Thu, 01 Sep 2011 05:00:00 GMT http://hdl.handle.net/10027/8410 2011-09-01T05:00:00Z