Structural characterization of phospholipids and peptides directly from tissue sections by MALDI traveling-wave ion mobility-mass spectrometry.

Ion mobility-mass spectrometry (IM-MS) provides rapid two-dimensional separations based on analyte apparent surface area or collision cross section (CCS, A(2)) and mass-to-charge, respectively. Recently, traveling-wave (t-wave) IM-MS was developed which uses electrodynamic rather than electrostatic fields commonly used in drift cell IM-MS instruments. The underlying theory for obtaining CCS data is well developed for drift cell IM-MS, while strategies for obtaining CCS values from t-wave IM-MS data remains an active area of research.

Structural and functional characterization of the monomeric U-box domain from E4B.

Substantial evidence has accumulated indicating a significant role for oligomerization in the function of E3 ubiquitin ligases. Among the many characterized E3 ligases, the yeast U-box protein Ufd2 and its mammalian homologue E4B appear to be unique in functioning as monomers. An E4B U-box domain construct (E4BU) has been subcloned, overexpressed in Escherichia coli, and purified, which enabled determination of a high-resolution NMR solution structure and detailed biophysical analysis.

Structure of the S100A6 complex with a fragment from the C-terminal domain of Siah-1 interacting protein: a novel mode for S100 protein target recognition.

S100A6 is a member of the S100 subfamily of EF-hand Ca (2+) binding proteins that has been shown to interact with calcyclin binding protein/Siah-1 interacting protein (CacyBP/SIP or SIP), a subunit of an SCF-like E3 ubiquitin ligase complex (SCF-TBL1) formed under genotoxic stress. SIP serves as a scaffold in this complex, linking the E2-recruiting module Siah-1 to the substrate-recruiting module Skp1-TBL1. A cell-based functional assay suggests that S100A6 modulates the activity of SCF-TBL1.

Profiling and imaging of tissues by imaging ion mobility-mass spectrometry.

Molecular profiling and imaging mass spectrometry (IMS) of tissues can often result in complex spectra that are difficult to interpret without additional information about specific signals. This report describes increasing data dimensionality in IMS by combining two-dimensional separations at each spatial location on the basis of imaging ion mobility-mass spectrometry (IM-MS). Analyte ions are separated on the basis of both ion-neutral collision cross section and m/z, which provides rapid separation of isobaric, but structurally distinct ions.