Typologie d'actualités: CBM

Enzymatic detection in near infrared optical imaging and MRI with a single ligand complexed to different lanthanide ions

The imaging visualization of active enzymes is of primary importance in biology.

In a collaborative effort between the Centre of Molecular Biophysics (CBM) and the Institute of Chemistry of Natural Substances (ICSN) in Gif sur Yvette, CBM researchers have designed Ln3+ complexes that provide enzyme-mediated changes in NIR luminescence, as well as in Chemical Exchange Saturation Transfer (CEST) and classical T1-weighted MRI, depending on the Ln3+ used. They have demonstrated the successful monitoring of b-galactosidase activity over time in NIR luminescence and CEST MR imaging in phantoms containing the Yb-complex, and in T1 MRI when using the Gd-analogue. A further great advantage of their probe design is its high versatility, as there are a large number of enzymatically cleavable groups that could be attached to the same core, thus creating probes for other important enzyme targets.

Reference : Rémy Jouclas, Sophie Laine, Svetlana V. Eliseeva, Jérémie Mandel, Frédéric Szeremeta, Pascal Retailleau, Jiefang He, Jean-Francois Gallard, Agnès Pallier, Célia S. Bonnet, Stéphane Petoud, Philippe Durand, Éva Tóth
Lanthanide-Based Probes for Imaging Detection of Enzyme Activities by NIR Luminescence, T1- and ParaCEST MRI
Angew. Chem. Int. Ed. 2024, https://onlinelibrary.wiley.com/doi/10.1002/anie.202317728

Comprehensive review about the “logic of protein modifications”

Among the main functional building blocks of living cells are proteins, small “molecular machines” produced by the cell according to the information encoded in genes. Each protein has its characteristic chemical composition which defines its structure and function.

In some circumstances, the chemical composition of a protein can be changed in an enzymatic process known as post-translational modification (PTM), whereby additional chemical groups are covalently attached to the protein. PTMs are used by the cell as a regulatory mechanism to control protein function. The addition of new chemical groups – which can come in different shapes and sizes, ranging from small groups, through sugars and lipids, to small proteins – changes the structure and interactions of a protein and can impact almost any aspect of its function.

Marcin Suskiewicz, a structural biologist and biochemist from the CBM, has devoted many years to studying various types of protein PTMs and currently supervises a project devoted to one particular type of PTMs, protein SUMOylation.

In the review published in the journal BioEssays, he reviews the history of the research into protein PTMs as well as various facets of this phenomenon, including the underlying chemical principles, molecular mechanisms, and evolution.

The review combines an introduction to the field with an overview of the recent literature and new ideas and hypotheses.

References:

The logic of protein post-translational modifications (PTMs): Chemistry, mechanisms and evolution of protein regulation through covalent attachments
Marcin Suskiewicz
BioEssays
First published:21 January 2024
https://doi-org.insb.bib.cnrs.fr/10.1002/bies.202300178