The structure of vaults has been worked out by the efforts of number of excellent scientists including Dr. John Heuser at Wash U, Dr. Tim Baker at Purdue, Dr. Joe Wall at Brookhaven, and Dr. Phoebe Stewart (originally at UCLA but currently at Vanderbilt). Vaults were recently crystallized by Dr. Dan Anderson and an x-ray crystal structure is being worked out by Dan and Dr. Stuart Sievers in Dr. David Eisenberg's laboratory here at UCLA. A summary of their results will be added to this website in the near future (stay tuned!).
Using an EM technique (figure above), John Heuser observed two very different vault conformations (an open and a closed form).
These forms suggest that inside cells, vaults may be able to open and close. This process was depicted by the model below which showed the closed form as a barrel which can open into two eight-petalled flowers surrounding and connected to a central ring.