Structural characterization of recombinant alpha-1-antitrypsin expressed in a human cell line.

Human alpha-1-antitrypsin (A1PI) is a plasma protein with the function of protecting lung tissues from proteolytic destruction by enzymes from inflammatory cells. A1PI deficiency is an inherited disorder associated with pulmonary emphysema and a higher risk of chronic obstructive pulmonary disease (COPD). Here we present the structural characterization of a recombinant form of human A1PI (Hu-recA1PI) expressed in the human PER.

Matrix-assisted laser desorption/ionization directed nano-electrospray ionization tandem mass spectrometric analysis for protein identification.

In those cases where the information obtained by peptide mass fingerprinting or matrix-assisted laser desorption/ionization tandem mass spectrometry (MALDI-MS/MS) is not sufficient for unambiguous protein identification, nano-electrospray ionization (nano-ESI) and/or electrospray ionization tandem mass spectrometry (ESI-MS/MS) analysis must be performed. The sensitivity of nano-ESI/MS, however, is lower than that of MALDI-MS, especially at very low analyte concentrations and/or in the presence of contaminants, such as salt and detergents. Moreover, to perform ESI-MS/MS, the peptide masses of the precursor ions must be known.

Chemical identification of a low abundance lysozyme peptide family bound to I-Ak histocompatibility molecules.

The processing by antigen-presenting cells (APC) of the protein hen egg-white lysozyme (HEL) results in the selection of a number of peptide families by the class II major histocompatibility complex (MHC) molecule, I-A(k). Some of these families are expressed in very small amounts, in the order of a few picomoles/10(9) APC. We detected these peptides from an extract of class II MHC molecules by using monoclonal anti-peptide antibodies to capture the MHC-bound peptides prior to their examination by HPLC tandem mass spectrometry.

In APCs, the autologous peptides selected by the diabetogenic I-Ag7 molecule are unique and determined by the amino acid changes in the P9 pocket.

We demonstrate in this study the great degree of specificity in peptides selected by a class II MHC molecule during processing. In this specific case of the diabetogenic I-A(g7) molecule, the P9 pocket of I-A(g7) plays a critical role in determining the final outcome of epitope selection, a conclusion that is important in interpreting the role of this molecule in autoimmunity. Specifically, we examined the display of naturally processed peptides from APCs expressing either I-A(g7) molecules or a mutant I-A(g7) molecule in which the beta57Ser residue was changed to an Asp residue.

Phenazine-1-carboxamide production in the biocontrol strain Pseudomonas chlororaphis PCL1391 is regulated by multiple factors secreted into the growth medium.

Pseudomonas chlororaphis PCL1391 controls tomato foot and root rot caused by Fusarium oxysporum f. sp. radicis-lycopersici.