Nock CM  Ball MS  White IR  Skehel JM  Bill L  Karuso P 《Rapid communications in mass spectrometry : RCM》2008,22(6):881-886

In order to identify putative biomarkers from two-dimensional (2D) gel electrophoresis it is necessary to use a visualization technique that is sensitive, has a large dynamic range and does not interfere with the identification of the protein. As mass spectrometry increases in sensitivity more pressure is placed on visualization techniques that facilitate proteomic workflows but do not interfere with downstream processing. Two stains reported to meet these requirements are SYPRO Ruby (Invitrogen) and Deep Purple (GE Healthcare). This study examined the compatibility of these stains with protein identification by selecting spots from replicate 2D gels of human plasma and subjecting these to protein identification using liquid chromatography/tandem mass spectrometry (LC/MS/MS). Using a test of two populations of proportions it was found that proteins were statistically more likely to be identified from gels stained with Deep Purple. Additionally, the identifications from Deep Purple stained gels are of higher quality because they are based on multiple peptides.  相似文献   

    

Christina Krywka Dr.  Christian Sternemann Dr.  Michael Paulus Dr.  Metin Tolan Prof. Dr.  Catherine Royer Prof. Dr.  Roland Winter Prof. Dr. 《Chemphyschem》2008,9(18):2809-2815

Herein, we explore the effect of different types of osmolytes on the high‐pressure stability and tertiary structure of a well‐characterized monomeric protein, staphylococcal nuclease (SNase). Changes in the denaturation pressure and the radius of gyration are obtained in the presence of different concentrations of trimethylamine N‐oxide (TMAO), glycerol and urea. To reveal structural changes in the protein upon compression at various osmolyte conditions, small‐angle X‐ray scattering (SAXS) experiments were carried out. To this end, a new high‐pressure cell suitable for high‐precision SAXS studies at synchrotron sources was built, which allows one to carry out scattering experiments up to maximum pressures of about 7 kbar. Our data clearly indicate that the osmolytes that stabilize proteins against temperature‐induced unfolding drastically increase their pressure stability and that the elliptically shaped curve of the pressure–temperature–stability diagram of proteins is shifted to higher temperatures and pressures with increasing osmolyte concentration. A drastic stabilization is observed for the osmolyte TMAO, which exhibits not only a significant stabilization against temperature‐induced unfolding, but also a particularly strong stabilization of the protein against pressure. In fact, such findings are in accordance with in vivo studies (for example P. J. Yancey, J. Exp. Biol. 2005 , 208, 2819–2830), where unusually high TMAO concentrations in some deep‐sea animals were found. Conversely, chaotropic agents such as urea have a strong destabilizing effect on both the temperature and pressure stability of the protein. Our data also indicate that sufficiently high TMAO concentrations might be able to largely offset the destabilizing effect of urea. The different scenarios observed are discussed in the context of recent experimental and theoretical studies.  相似文献   

    

Thiele CM  Bermel W 《Magnetic resonance in chemistry : MRC》2007,45(10):889-894

Owing to the recent developments concerning residual dipolar couplings (RDCs), the interest in methods for the accurate determination of coupling constants is renascenting. We intended to use the J-modulated ADEQUATE experiment by K?vér et al. for the measurement of (13)C - (13)C coupling constants at natural abundance. The use of adiabatic composite chirp pulses instead of the conventional 180 degrees pulses, which compensate for the offset dependence of (13)C 180 degrees pulses, led to irregularities of the line shapes in the indirect dimension causing deviations of the extracted coupling constants. This behaviour was attributed to coupling evolution, during the time of the adiabatic pulse (2 ms), in the J-modulation spin echo. The replacement of this pulse by different kinds of refocusing pulses indicated that a pair of BIPs (broadband inversion pulses), which behave only partially adiabatic, leads to correct line shapes and coupling constants conserving the good sensitivity obtained with adiabatic pulses.  相似文献   

    

Samuel M. Mugo  Christina S. Bottaro 《Rapid communications in mass spectrometry : RCM》2007,21(2):219-228

Aquatic fulvic acids (AFAs) are demonstrated to be effective matrices for the analysis of various polar compounds (ranging from 100–1500 Da) by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS). The efficiency of AFA as a matrix is shown for a wide range of test compounds, including a number of carbohydrates, cyclodextrins and peptides, with typical detection limits of ～10 µg mL^?1. The propensity of AFA to enhance ionization through protonation of peptides, and formation of sodium and potassium adducts of carbohydrates and polyethylene glycol, was noted. Differences were observed in the performances of the two AFA matrices used, a Suwannee River, International Humic Substances Society (IHSS) standard and a locally extracted fulvic acid (LFA). For example, in the analysis of carbohydrate standards, the use of the LFA matrix typically doubled the analyte ion signal intensities and resulted in signal‐to‐noise (S/N) ratios that were 2–4 times better than when the Suwannee River AFA matrix was used. AFA was also used in the analysis of real‐world samples without extraction or purification; cantaloupe juice and acetaminophen tablets were analyzed, and glucose and acetaminophen could easily be identified as respective components. When lower concentrations of fulvic acid were used in the presence of sugars, a reversal of roles was observed in which the sugars functioned as the matrix and significantly enhanced ionization of the AFA components, while ions associated with the sugars themselves were suppressed or absent. Effective as a matrix for a variety of analytes and widely available, AFA is an attractive environmentally friendly choice for use in MALDI applications. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

    

Dietmar Ohlmann  Christina M. Marchand  Hansjrg Grützmacher  Grace Shiahuy Chen  David Farmer  Rainer Glaser  Antonio Currao  Reinhard Nesper  Hans Pritzkow 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》1996,108(3):317-320

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Nils‐Fredrik&#x;K. Kaiser  Ulf Bremberg  Mats Larhed  Christina Moberg  Anders Hallberg 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2000,112(20):3741-3744

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Christina Moberg 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》1998,110(3):260-281

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Horst Kisch  Ling Zang  Christian Lange  Wilhelm F. Maier  Christina Antonius  Dieter Meissner 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》1998,110(21):3201-3203

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Joseph M. Keca  Juan Chen  Marta Overchuk  Nidal Muhanna  Christina M. MacLaughlin  Cheng S. Jin  Warren D. Foltz  Jonathan C. Irish  Prof. Dr. Gang Zheng 《Angewandte Chemie (International ed. in English)》2016,55(21):6187-6191

The discovery and synthesis of novel multifunctional organic building blocks for nanoparticles is challenging. Texaphyrin macrocycles are capable and multifunctional chelators. However, they remain elusive as building blocks for nanoparticles because of the difficulty associated with synthesis of texaphyrin constructs capable of self‐assembly. A novel manganese (Mn)‐texaphyrin‐phospholipid building block is described, along with its one‐pot synthesis and self‐assembly into a Mn‐nanotexaphyrin. This nanoparticle possesses strong resilience to manganese dissociation, structural stability, in vivo bio‐safety, and structure‐dependent T₁ and T₂ relaxivities. Magnetic resonance imaging (MRI) contrast enhanced visualization of lymphatic drainage is demonstrated with respect to proximal lymph nodes on the head and neck VX‐2 tumors of a rabbit. Synthesis of 17 additional metallo‐texaphyrin building blocks suggests that this novel one‐pot synthetic procedure for nanotexaphyrins may lead to a wide range of applications in the field of nanomedicines.  相似文献   

    

Alessandra Tata  Mateus J. Sudano  Vanessa G. Santos  Fernanda D.C. Landim‐Alvarenga  Christina R. Ferreira  Marcos N. Eberlin 《Journal of mass spectrometry : JMS》2013,48(7):844-849

In pre‐implantation embryos, lipids play key roles in determining viability, cryopreservation and implantation properties, but often their analysis is analytically challenging because of the few picograms of analytes present in each of them. Matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) allows obtaining individual phospholipid profiles of these microscopic organisms. This technique is sensitive enough to enable analysis of individual intact embryos and monitoring the changes in membrane lipid composition in the early stages of development serving as screening method for studies of biology and biotechnologies of reproduction. This article introduces an improved, more comprehensive MALDI‐MS lipid fingerprinting approach that considerably increases the lipid information obtained from a single embryo. Using bovine embryos as a biological model, we have also tested optimal sample storage and handling conditions before the MALDI‐MS analysis. Improved information at the molecular level is provided by the use of a binary matrix that enables phosphatidylcholines, sphingomyelins, phosphatidylserines, phosphatidylinositols and phosphoethanolamines to be detected via MALDI(±)‐MS in both the positive and negative ion modes. An optimal MALDI‐MS protocol for lipidomic monitoring of a single intact embryo is therefore reported with potential applications in human and animal reproduction, cell development and stem cell research. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献