Immunoglobulin structure and function as revealed by electron microscopy.

Electron-microscopic (EM) analysis preceded crystallographic analysis [1,2] of Igs by over a decade and was for a time the only direct way of analyzing their 3-D molecular structure. Once the X-ray structures were deduced, the role of EM gradually shifted from gross structural analysis to the addressing of more sophisticated structural and functional questions. EM remains a vital adjunct to the many physicochemical, biochemical, and serological tools brought to bear on these remarkable molecules as we try to relate form to function. In this review I will highlight some of the many contributions that have been made possible by virtue of being able to 'see' Ig molecules and immune complexes.