Grand Séminaire d'Institut

Vendredi 21 Juin 2024 à 11h00.

Zapping ions – coupling an FTICR with UV and IR lasers for better top-down mass spectrometry

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Efficient and informative fragmentation is key to the success of many MS-based experiments studying both small molecules as well as large multi-protein assemblies. Especially so, in the case of proteins, since the realization of both structural biologists and mass spectrometrists that there exists a level of complexity involved in the regulation and controlling of protein structure and function beyond pure “single gene = single protein” equation. Through RNA splicing, mutations as well as post- and co-translational modifications and involvement in larger non-covalent assemblies, individual proteins generate complex landscapes of proteoforms with huge implications on their functioning in organisms.

Therefore, both proteomics as well as structural MS have been dependent on various means of fragmentation for which diverse MS dissociation techniques and their combinations are often needed. This contribution will report on the successful implementation of both 10.6 µm CO2 and 193 nm ArF lasers for infrared multi-photon dissociation (IRMPD) and ultraviolet photodissociation (UVPD), respectively, for in‑cell dissociation inside the 15T SolariX Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometer at BIOCEV in Prague. It will also highlight a particular success story, where the molecular structure of nostatin A – a novel polypeptidic highly bioactive compound synthesized and heavily co-translationally modified in algae has been solved by top-down MS/MS after years of resisting efforts to crystallize it or determine it using nuclear magnetic resonance alone.

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