CRYSTAL STRUCTURE OF HUMAN PURINE NUCLEOSIDE PHOSPHORYLASE IN COMPLEX WITH SERME-IMMUCILLIN H TRANSFERASE, TRANSITION STATE ANALOG INHIBITOR, HPNP, PNP, IMMUCILLIN H, SERME-IMMH, ACETYLATION, CYTOPLASM, CYTOSKELETON, DISEASE MUTATION, GLYCOSYLTRANSFERASE, POLYMORPHISM 3K8Q