Studies of Aggregates of Two Muscle Proteins with Scanning Transmission and Conventional Transmission Electron Microscopy
Studies of the structures of various aggregates of proteins from vertebrate striated muscle have begun, using in particular the scanning transmission electron microscope (STEM). The high collection efficiency of this microscope has been noted elsewhere and the contrast advantage and signal selection capabilities have been demonstrated.Although the instrument can produce high contrast images of unstained and unfixed biological material, it is not clear which preparation methods might maintain the native structure of such material. So the study begins on familiar ground with conventionl negatively stained preparations, While later steps will include less conventional methods.Rabbit tropomyosin Mg-tactoids in suspension were received from Dr. Carolyn Cohen (of Children's Cancer Research Foundation, Boston). The tactoids have a primary periodicity of 395 Å. Isolated myofibrils were obtained from Joseph Etlinger (of this University); myosin was extracted from them by a method similar to that of Dow and Stracher.