Home About us Contact
|
Home About us Contact | ||
|
|
||
Single Peptide (single + peptide)
Selected AbstractsPurification and characterization of a bacteriocin-like compound (Lichenin) produced anaerobically by Bacillus licheniformis isolated from water buffaloJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2001P. Pattnaik Aims:,To characterize a bacteriocin-like factor from Bacillus licheniformis 26 L-10/3RA isolated from buffalo rumen. Methods and Results:,The culture supernatant exhibited the antibacterial activity against a number of indicator organisms in a cut-well agar assay under anaerobic conditions. The inhibitory component was purified by following ammonium sulphate precipitation, gel filtration and ion exchange chromatography and confirmed to be a single peptide. A single band on tricine-sodium dodecyl sulphate-polyacrylamide gel electrophoresis confirmed that the peptide was purified to homogeneity and having an estimated molecular mass of approximately 1400 dalton. Complete amino acid sequence of the peptide yielded 12 amino acids from the N-terminal end (ISLEICXIFHDN). No homology with previously reported bacteriocins was observed and has been designated as Lichenin. Lichenin was found to be hydrophobic, sensitive to atmospheric oxygen, retained biological activity even after boiling for 10 min and was active over a pH range of 4·0,9·0. Conclusions:,The Lichenin represents the first anaerobiosis specific expression of bacteriocin-like compound isolated from Bacillus licheniformis 26 L-10/3RA of buffalo rumen origin. Significance and Impact of the Study:,Lichenin could be a potential condidate for manipulating the rumen function at molecular level intended for improving the productivity of the ruminant. [source] Simulation and Experiment of Temperature and Cosolvent Effects in Reversed Phase Chromatography of PeptidesBIOTECHNOLOGY PROGRESS, Issue 3 2005Kosta Makrodimitris Experiments and simulations have been carried out for several polar protected peptides in reversed phase chromatography in order to demonstrate how simulation can describe the effects of varying temperature and cosolvent fraction. Comparisons of adsorption chemical potentials from mesoscopic simulations and experimental chromatographic retention data show very good agreement with only one temperature-independent solvent parameter from a single peptide. Such simulations should help guide the design of chromatography experiments with biomolecules and predict retention, including conditions for which empirical correlations such as hydrophobicity scales and molecular descriptors have not been developed. [source] Investigation of tyrosine nitration in proteins by mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 6 2001Ann-Sofi Petersson Abstract In vivo nitration of tyrosine residues is a post-translational modification mediated by peroxynitrite that may be involved in a number of diseases. The aim of this study was to evaluate possibilities for site-specific detection of tyrosine nitration by mass spectrometry. Angiotensin II and bovine serum albumin (BSA) nitrated with tetranitromethane (TNM) were used as model compounds. Three strategies were investigated: (i) analysis of single peptides and protein digests by matrix-assisted laser desorption/ionization (MALDI) peptide mass mapping, (ii) peptide mass mapping by electrospray ionization (ESI) mass spectrometry and (iii) screening for nitration by selective detection of the immonium ion of nitrotyrosine by precursor ion scanning with subsequent sequencing of the modified peptides. The MALDI time-of-flight mass spectrum of nitrated angiotensin II showed an unexpected prompt fragmentation involving the nitro group, in contrast to ESI-MS, where no fragmentation of nitrated angiotensin II was observed. The ESI mass spectra showed that mono- and dinitrated angiotensin II were obtained after treatment with TNM. ESI-MS/MS revealed that the mononitrated angiotensin II was nitrated on the side-chain of tyrosine. The dinitrated angiotensin II contained two nitro groups on the tyrosine residue. Nitration of BSA was confirmed by Western blotting with an antibody against nitrotyrosine and the sites for nitration were investigated by peptide mass mapping after in-gel digestion. Direct mass mapping by ESI revealed that two peptides were nitrated. Precursor ion scanning for the immonium ion for nitrotyrosine revealed two additional partially nitrated peptides. Based on the studies with the two model compounds, we suggest that the investigation of in vivo nitration of tyrosine and identification of nitrated peptides might be performed by precursor ion scanning for the specific immonium ion at m/z 181.06 combined with ESI-MS/MS for identification of the specific nitration sites. Copyright © 2001 John Wiley & Sons, Ltd. [source] Identification of immunodominant CD4+ T cell epitopes in patients with Yersinia -induced reactive arthritis by cytometric cytokine secretion assayARTHRITIS & RHEUMATISM, Issue 11 2006Andreas Thiel Objective In reactive arthritis (ReA), a bacteria-specific T cell response to the triggering microbe is detected in synovial fluid. So far, direct characterization of bacteria-specific T cells and identification of the immunodominant fine specificities remain difficult due to the lack of appropriate techniques. The aim of the present study was to directly determine the fine specificity of CD4+ T cells specific to ReA-associated bacteria-derived protein. Methods In 2 patients with Yersinia -induced ReA, live Yersinia Hsp60,specific CD4+ T cells were directly isolated from synovial fluid after stimulation with Yersinia -derived protein Hsp60 using a cytometric cytokine secretion assay. Generated short-term T cell lines were then tested in vitro for their peptide epitope specificity. Also, direct cross-reactivity of one line with Chlamydia - and human-derived Hsp60 was assessed. Results Generated short-term CD4+ T cell lines were highly antigen-specific and revealed single immunodominant peptide epitopes that were confirmed by direct testing with single peptides in both peripheral blood and synovial fluid cells. Yersinia Hsp60,specific T cells of one patient cross-reacted directly with human Hsp60. Conclusion Our results demonstrate the feasibility of direct assessment of live, potentially pathogenic, antigen-specific interferon-,+ CD4+ T cells taken from inflammatory lesions of patients with rheumatic diseases such as ReA. This might have implications not only regarding pathogenesis, but also in the design of new immunotherapies. [source] | ||||||||||