Optimizing electrospray interfaces using slowly diverging conical duct (ConDuct) electrodes.

We demonstrate that the efficiency of ion transmission from atmosphere to vacuum through stainless steel electrodes that contain slowly divergent conical duct (ConDuct) channels can be close to 100%. Here, we explore the properties of 2.5-cm-long electrodes with angles of divergence of 0°, 1°, 2°, 3°, 5°, 8°, 13°, and 21°, respectively.

Maximizing ion transmission from atmospheric pressure into the vacuum of mass spectrometers with a novel electrospray interface.

We have discovered that an electrode containing a conical channel with a small angular divergence can transmit into the vacuum almost 100% of an electrospray ion current produced at atmospheric pressure. Our first implementation of such a conical duct, which we term "ConDuct," uses a conductive plastic pipette tip containing an approximately 1.6° divergent channel at its entrance.

See & Catch method for studying protein complexes in yeast cells: a technique unifying fluorescence microscopy and mass spectrometry.

We have developed a method for studying proteins and protein complexes in yeast cells based on unification of fluorescence microscopy and mass spectrometry techniques. To apply the method, termed by us as "See & Catch," we first produced a variety of DNA plasmids used as PCR templates for genomic tagging of proteins with a modular fluorescent and affinity tags. The modular tag consists of one of the multiple versions of monomeric fluorescent proteins fused to a variety of small affinity epitopes.

Quantitative encoding of the effect of a partial agonist on individual opioid receptors by multisite phosphorylation and threshold detection.

In comparison to endogenous ligands of seven-transmembrane receptors, which typically act as full agonists, many drugs act as partial agonists. Partial agonism is best described as a "macroscopic" property that is manifest at the level of physiological systems or cell populations; however, whether partial agonists also encode discrete regulatory information at the "microscopic" level of individual receptors is not known. Here, we addressed this question by focusing on morphine, a partial agonist drug for μ-type opioid peptide receptors (MORs), and by combining quantitative mass spectrometry with cell biological analysis to investigate the reduced efficacy of morphine, compared to that of a peptide full agonist, in promoting receptor endocytosis.

High-Capacity Ion Trap Coupled to a Time-of-Flight Mass Spectrometer for Comprehensive Linked Scans with no Scanning Losses.

A high-capacity ion trap coupled to a time-of-flight (TOF) mass spectrometer has been developed to carry out comprehensive linked scan analysis of all stored ions in the ion trap. The approach involves a novel tapered geometry high-capacity ion trap that can store more than 10(6) ions (range 800-4000 m/z) without degrading its performance. Ions are stored and scanned out from the high-capacity ion trap as a function of m/z, collisionally fragmented and analyzed by TOF.