Yassel Ramos

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Here we present a procedure for peptide fractionation by SDS-free polyacrylamide gel electrophoresis, based on discontinuous buffer systems. In the absence of SDS, peptide migration depends both on their molecular mass and on their net charge at the electrophoresis pH. By selecting the separation pH, peptide mobility is modulated. In the original(More)
Dengue is currently one of the most important arthropod-borne diseases, causing up to 25,000 deaths annually. There is currently no vaccine to prevent dengue virus infection, which needs a tetravalent vaccine approach. In this work, we describe the cloning and expression in Escherichia coli of envelope domain III-capsid chimeric proteins (DIIIC) of the four(More)
CIGB-300 is a proapoptotic peptide-based drug that abrogates the CK2-mediated phosphorylation. This peptide has antineoplastic effect on lung cancer cells in vitro and in vivo. To understand the mechanisms involved on such anticancer activity, the NCI-H125 cell line proteomic profile after short-term incubation (45 min) with CIGB-300 was investigated. As(More)
Bm95 is an antigen isolated from Boophilus microplus strains with low susceptibility to antibodies developed in cattle vaccinated with the recombinant Bm86 antigen (Gavac, HeberBiotec S.A., Cuba). It is a Bm86-like surface protein, which by similarity contains seven EGF-like domains and a lipid-binding GPI-anchor site at the C-terminal region. The primary(More)
Tamoxifen is the most frequently used drug for hormone therapy of breast cancer patients, even though a high percentage of women are (or become) refractory to this treatment. The proteins involved in tamoxifen resistance of breast tumor cells as well as the mechanisms by which they interact, are still unknown. Some years ago, we established the xenograft(More)
SDS-free polyacrylamide gel electrophoresis is an effective alternative approach to peptide fractionation. Here we describe a discontinuous buffer system at acid pH that improves the separation of acidic peptides from tryptic digestion. MOPS and chloride act as trailing and leading ions, respectively, in this system, while histidine operates as counterion(More)
Protein identification by mass spectrometry is mainly based on MS/MS spectra and the accuracy of molecular mass determination. However, the high complexity and dynamic ranges for any species of proteomic samples, surpass the separation capacity and detection power of the most advanced multidimensional liquid chromatographs and mass spectrometers. Only a(More)
IPG (Immobilized pH Gradient) based separations are frequently used as the first step in shotgun proteomics methods; it yields an increase in both the dynamic range and resolution of peptide separation prior to the LC-MS analysis. Experimental isoelectric point (pI) values can improve peptide identifications in conjunction with MS/MS information. Thus,(More)
Mass spectrometry is now firmly established as a powerful technique for the identification and characterization of proteins when used in conjunction with sequence databases. Various approaches involving stable-isotope labeling have been developed for quantitative comparisons between paired samples in proteomic expression analysis by mass spectrometry.(More)
Here we demonstrate the usefulness of peptide fractionation by SDS-free polyacrylamide gel electrophoresis and its applicability to proteomics studies. In the absence of SDS, the driving force for the electrophoretic migration toward the anode is supplied by negatively charged acidic amino acid residues and other residues as phosphate, sulfate and sialic(More)