WPMLG-5 spectroscopy of self-aggregated BChl e in natural chlorosomes of Chlorobaculum Limnaeum

¹H magic angle spinning (MAS) nuclear magnetic resonance (NMR), employing rapid spinning and the wPMLG-5 pulse sequence, was used to explore the possibility for performing ¹H solid state NMR of a light-harvesting organelle, the chlorosome antenna of Chlorobaculum limnaeum. This natural antenna system is built from bacteriochlorophyll e (BChl e) molecules that are self-assembled to form a supramolecular scaffold for in vivo harvesting of light. We present preliminary data on this chlorosome species and address the feasibility of performing wPMLG spectroscopy, in terms of high power irradiation on a fragile biological sample. In parallel, enhancing the ¹H shift dispersion from the magnetic field can help to resolve signals from protons that resonate downfield. Different line narrowing mechanisms operating in parallel provide access to resolving selected ¹H signals collected from the moderately sized and chemically diverse BChl e molecular motif in the chlorosome scaffold. These discoveries will be helpful for future studies of structural and functional characteristics of self-assembled natural and artificial light-harvesting molecules.