Pleiner et al. eLife doi:10.7554/eLife.11349 (3 December 2015).

Conventional antibodies can add tens of nanometers to the size of a structure that they label. Single-chain camelid antibodies, or 'nanobodies', are exciting because of their potential as much smaller protein labels, and they should enable more quantitative measurements of macromolecular structures. Pleiner et al. report a series of nanobodies that target components of the nuclear pore complex (NPC). They demonstrate that these tools can be prepared via cytoplasmic expression (as opposed to secretion into the bacterial periplasm) and conjugated to fluorophores at added surface cysteines using maleimide chemistry, apparently without disrupting their function. They used the fluorophore-labeled tools for localization-based super-resolution imaging of NPCs and also demonstrate purification of endogenous complexes via nanobodies fused to an affinity tag.