What’s New in Mass Spec?

Natural defense. To protect themselves against predators, velvet worms (Onychophora) expel a protein based slime – forming stiff and stable fibers after dehydration. An international research team recently examined the molecular structure of the worm’s defense slime – in hopes of characterizing the chemical modifications occurring to create those threads. The scientists employed high-resolution nuclear magnetic resonance (NMR), natural abundance dynamic nuclear polarization (DNP), and mass spectrometry to reveal phosphonate as the key compound responsible for this fiber-turning modification. “These fibers can dissolve back into their precursor proteins in water, after which they can be drawn into new fibers, providing biological inspiration to design recyclable materials,” said the authors. 

Revealing Ryugu. Following the Hayabusa2 space mission, researchers have performed preliminary chemical analysis of samples from the Ryugu asteroid that orbits the sun between Earth and Mars. The samples were digested in acids and subjected to inductively coupled plasma mass spectrometry (ICP-MS) and thermal ionization mass spectrometry (TIMS). The researchers found variance in isotopes of chromium depending on where the sample was collected on the asteroid, which indicates that water was moving around on the parent body of Ryugu, shaping the distribution of elements. In the press release, lead author Tetsuya Yokoyama explained that these samples “are unaffected by terrestrial contamination, and they are particularly valuable for unraveling the earliest history of the solar system as they retain primitive chemical characteristics”.

Structural surfaceomics. Despite cellular therapies becoming increasingly popular, there are still significant challenges to overcome – such as the lack of cancer related surface biomarkers. Researchers from Canada, Germany, and the USA have collaborated and introduced a new strategy to target and characterize cancer-specific protein conformations on the surface  of tumor cells. “Structural surfaceomics” combines cross-linking mass spectrometry with cell surface capture (CSC) to define protein-protein interactions, specifically of surface N-linked glycoproteins. The team successfully applied surfaceomics to an acute myeloid leukemia (AML) model – identifying the activated form of integrin beta 2 (β2) as a potential immunotherapeutic target. 

“Our structural surfaceomics approach presented here, integrating XL–MS with cell surface glycoprotein enrichment, is a technology designed to expand the targetable space of cell surface immunotherapy antigens. This strategy may also carry promise in applications in other basic or translational science fields,” concluded the authors.

Towards a differential diagnosis of BD and MDD. Bipolar disorder (BD) can be distinguished from major depressive disorder (MDD) during episodes of low mood by profiling biomarkers in patient dried blood spots (DBSs), according to a study from the University of Cambridge, UK. The researchers used a targeted mass spectrometry-based metabolomic platform to analyze DBS metabolites and a questionnaire to assess current depressive symptoms. “This study provides a proof of concept for developing an accessible biomarker test to facilitate the differential diagnosis of BD and MDD and highlights the potential involvement of ceramides in the pathophysiological mechanisms of mood disorders,” concluded the authors.