Project Summary/Abstract This request is for a large-field-of-view direct electron detector with high quantum efficiency to enable in situ cryo- electron tomography and high-resolution single-particle cryo-electron microscopy at the Rutgers CryoEM & Nanoimaging Facility (RCNF). This detector will at least treble data throughput, which is enables us to solve series of related structures for mechanistic insights (for instance, transcription/translation coupling complexes bridged by RfaH that differ in the length of RNA between the polymerase and ribosome). The high throughput plus the increased signal will allow us to solve more heterogeneous and flexible structures such as the destabilized nucleosome in complex with Nucleosome Destabilizing Factor. The large field of view will be key for in situ tomography of [], of transcription/translation coupling inside E. coli minicells, and of understanding how gene therapy vectors deliver therapeutic DNA. The electron detector will be mounted on our existing cryo-transmission electron microscope and operated as part of a university core facility with training, support, and consultation from the expert RCNF staff members available to intramural and extramural investigators. The RCNF operates on a university-subsidized recharge basis and there is institutional commitment to maintain and service the equipment.