The three-dimensional structure of three proteins which play regulatory roles in the growth of normal and tumor cells will be investigated. These proteins are (1) neocarzinostatin (NCS), an anti-tumor protein isolated from Streptomyces carzinostations of MW 10,700; (2) L-glutaminase-asparaginase (GLA) from Acinetobacter, another anti-tumor protein containing four subunits (MW 33,000 each); (3) nerve growth factor (NGF), a small protein (MW 26,500) from mouse submaxillary glands which enhances growth and development of sympathetic and embryonic sensory nerve cells. An objective of these studies is to understand on a molecular level how certain steric modifications of these regulatory proteins enhance activity (and often for the anti-tumor proteins decrease toxicity). NCS and GLA have already been crystallized and crystallization of NGF and growth of large GLA crystals will be attempted by standard techniques including vapor diffusion, microdiffusion and a batch survey micro technique. Heavy atom derivatives (Sm(NO3)3 of NCS and iodinated NGF) will be prepared by soaking pregrown crystals or recrystallizing the derivatives. Structures will be determined using X-ray diffraction techniques. Crystal diffraction will be studied not only with conventional sources using large crystals but also using novel synchrotron radiation. Because of the very high intensity and tunability of this unconventional source, the study of smaller crystals and the attainment of unprecedented accuracy through the use of anomalous scattering techniques will be possible. A diffraction camera will be adapted to the focusing monochromator designed by another group, and techniques for camera alignment and data collection will be determined using protein crystals of known structure. An automated scanning densitometer, interfaced to our PDP 11/45 computer will be used for rapid data reduction.