In the broadest sense, we would like to determine the Fundamental principles from which proteins derive their function. this requires, firstly, a knowledge of the polypeptide fold and, secondly, precise information on the inter-relationship of the chemical groups that determine substrate binding and catalysis. A comparison of related structures will help in differentiating the important features from the less important differences. It is, however, the differences in sturcture which relate to the particular properties of isozymes or related enzymes. We are pursuing these studies by investigating the three-dimensional structure of a series of enzymes in the glycolytic pathway using X-ray crystallography. In part, we plan to carefully refine a large number of structures previously determined in our laboratory and, in part, to analyze new structures. Our present work can be subdivided as follows: A. Lactate Dehydrogenase (LDH) 1. Structures to be refined a. Dogfish apo M4 LDH and its bound ligands b. Dogfish ternary M4 LDH and various bound coenzyme of substrate analogues c. Pig ternary H4 LDH in two different ternary complexes d. Mouse testes C4 LDH (LDH-X) 2. Structures to be determined and refined (excellent crystals are available) a. B. stearothermophilus apo LDH b. B. stearothermophilus binary LDH including the FDP effector B. Glyceraldehyde-3-phosphate dehydrogenase 1. Structures to be refined a. The holo lobster enzyme and various coenzyme and substrate analogues b. The apo lobster enzyme C. Phosphoglucomutase rabbit enzyme - the structure is to be determined and refined (excellent crystals are available)
