Top-Down Analysis of In-Source HDX of Native Protein Ions.

Hydrogen/deuterium exchange (HDX) is used in protein biophysics to probe folding dynamics, intermolecular interactions, epitope and other mapping. A typical procedure often involves HDX in buffered DO solution followed by pepsin digestion, and liquid chromatography/electrospray ionization mass spectrometry analysis. In this work, HDX of protein ions was conducted in the ESI source.

The Ebola Viral Protein 35 N-Terminus Is a Parallel Tetramer.

Members of Mononegavirales, the order that includes nonsegmented negative sense RNA viruses (NNSVs), encode a small number of multifunctional proteins. In members of the Filoviridae family, virus protein 35 (VP35) facilitates immune evasion and functions as an obligatory cofactor for viral RNA synthesis. VP35 functions in a manner orthologous to that of phosphoproteins from other NNSVs.

On-line desalting of crude oil in the source region of a Fourier transform ion cyclotron resonance mass spectrometer.

The presence of dissolved metal ions in waters associated with crude oils has many negative implications for the transport, processing, and refining of petroleum. In addition, mass spectrometric analysis of sodium containing crude oil samples suffers from ionization suppression, unwanted adduct formation, and an increase in the complexity of data analysis. Here, we describe a method for the reduction/elimination of these adverse effects by modification of the source region gas-inlet system of a 12 T Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer.

Charge State Dependent Fragmentation of Gaseous α-Synuclein Cations via Ion Trap and Beam-Type Collisional Activation.

Ions derived from nano-electrospray ionization (nano-ESI) of α-synuclein, a 14.5 kDa, 140 amino acid residue protein that is a major component of the Lewy bodies associated with Parkinson's disease, have been subjected to ion trap and beam-type collisional activation. The former samples products from fragmentation at rates generally lower than 100 s(-1) whereas the latter samples products from fragmentation at rates generally greater than 10(3) s(-1).

Solid-phase synthesis of alpha-glucosamine sulfoforms with fragmentation analysis by tandem mass spectrometry.

Sulfated epitopes of alpha-glucosamine (GlcN sulfoforms) were prepared by solid-phase synthesis as models of internal glucosamines within heparan sulfate. An orthogonally protected 2'-hydroxyethyl GlcN derivative was immobilized on a trityl resin support and subjected to regioselective deprotection and sulfonation conditions, which were optimized with the aid of on-resin infrared or Raman analysis. The sulfoforms were cleaved from the resin under mild Lewis acid conditions without affecting the O- or N-sulfate groups and purified by reversed-phase high-performance liquid chromatography (HPLC).