*About the job*As a Postdoctoral Fellow in the Biophysics & BioNMR / BioAnalytics team, you will investigate how Post Translational Modifications (PTMs) in antibody CDRs affects antigen binding and molecular stability.This project aims to develop a comprehensive methodology combining experimental structural biology (2D/3D-NMR, cryo-EM, crystallography, HDX-MS) with computational modelling to elucidate how PTMs in CDR modulate Fab structure and antigen recognition.Your work will directly support molecule optimization and manufacturing process development.**About Sanofi:**We’re an R&D-driven, AI-powered biopharma company committed to improving people’s lives and delivering compelling growth. Our deep understanding of the immune system – and innovative pipeline – enables us to invent medicines and vaccines that treat and protect millions of people around the world. Together, we chase the miracles of science to improve people’s lives.**Main responsibilities:*** Produce and characterize samples with different levels of modification by mass spectrometry, SEC, DSC and binding assays.* Perform 2D-NMR analysis on modified and unmodified mAb/Fab samples to map chemical shift perturbations and identify structural signatures induced by PTMs.* Produce samples via cell-free expression.* Structurally characterize the Fab-antigen interaction by NMR, cryo-EM, crystallography and HDX-MS data, to provide an integrated view of how PTMs modulate binding and stability.* Design, produce and evaluate mutated Fab constructs to determine the role of residues neighboring the PTMs binding affinity and molecular stability.* Present findings to cross-functional teams and contribute to scientific publications.*About you** **Education:** PhD in NMR spectroscopy, structural biology, biophysics or a related field* **Experience & technical skills:** Hands-on expertise in protein production including U-13C, 15N and 2H isotope labelling and specific methyl labelling; proven experience in NMR assignment of high molecular weight proteins (backbone and methyl groups)* **Languages:** Fluent English, intermediate level of French* **Soft skills:** Strong analytical mindset, curiosity, autonomy, and ability to collaborate within a multidisciplinary team*Why choose us?** Learn from inspiring mentors and collaborative teams while contributing to real projects that shape the future of healthcare.* Launch your career with a company that invests in you — and empowers you to reimagine what’s possible.* Enjoy opportunities to collaborate beyond your area of expertise, working with diverse teams across science to spark new ideas and drive breakthroughs.* Work at the forefront of drug discovery, harnessing cutting-edge AI, data, and digital platforms to push the boundaries of science.* Join a workplace where diversity, equity, and inclusion are at the core, with Employee Resource Groups and leadership programs that celebrate every voice.**Pursue** *Progress*. **Discover** *Extraordinary*.Join Sanofi and step into a new era of science - where your growth can be just as transformative as the work we do. We invest in you to reach further, think faster, and do what’s never-been-done-before. You’ll help push boundaries, challenge convention, and build smarter solutions that reach the communities we serve. Ready to chase the miracles of science and improve people’s lives? Let’s Pursue *Progress* and Discover *Extraordinary* – together.