Quantitative evaluation of refolding conditions for a disulfide-bond-containing protein using a concise ¹⁸O-labeling technique.

A concise method was developed for quantifying native disulfide-bond formation in proteins using isotopically labeled internal standards, which were easily prepared with proteolytic ¹⁸O-labeling. As the method has much higher throughput to estimate the amounts of fragments possessing native disulfide arrangements by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) than the conventional high performance liquid chromatography (HPLC) analyses, it allows many different experimental conditions to be assessed in a short time. The method was applied to refolding experiments of a recombinant neuregulin 1-β1 EGF-like motif (NRG1-β1), and the optimum conditions for preparing native NRG1-β1 were obtained by quantitative comparisons.

Analysis of Ras-induced oncogenic transformation of NIH-3T3 cells using differential-display 2-DE proteomics.

Ras proteins control at least three crucial signalling networks responsible for several cellular processes including anchorage independence, survival, and proliferation. Point mutations in one of the three ras genes are frequent in human tumours. In these tumours, Ras oncoproteins contribute significantly to the malignant phenotype, including deregulation of tumour-cell growth, apoptosis and invasiveness, and the ability to induce angiogenesis.

Dual-purpose sample trap for on-line strong cation-exchange chromatography/reversed-phase liquid chromatography/tandem mass spectrometry for shotgun proteomics. Application to the human Jurkat T-cell proteome.

A dual-purpose sample-trapping column is introduced for the capacity enhancement of proteome analysis in on-line two-dimensional nanoflow liquid chromatography (strong cation-exchange chromatography followed by reversed-phase liquid chromatography) and tandem mass spectrometry. A home-made dual trap is prepared by sequentially packing C18 reversed-phase (RP) particles and SCX resin in a silica capillary tubing (1.5 cm x 200 microm I.

Crystallization and preliminary X-ray crystallographic analysis of malonyl-CoA decarboxylase from Rhizobium leguminosarum bv. trifolii.

Malonyl-CoA decarboxylase (MCD), which catalyzes the conversion of malonyl-CoA to acetyl-CoA, is an evolutionarily distinct and highly conserved enzyme. MCD does not share sequence homology with other known decarboxylases, while the enzymes from different species exhibit at least >30% sequence identity to each other. In order to provide a canonical structure of the enzyme for detailed study of its structure-function relationship, the MCD of Rhizobium leguminosarum bv.