Acetylcholinesterase (AChE) terminates nerve-impulse transmission at cholinergic synapses by rapid hydrolysis of the neurotransmitter, acetylcholine. Substrate traffic in AChE involves at least two binding sites, the catalytic and peripheral anionic sites, which have been suggested to be allosterically related and involved in substrate inhibition. Here, we present the crystal structures of Torp...

The major facilitator superfamily represents the largest group of secondary membrane transporters in the cell. Here we report the 3.3 angstrom resolution structure of a member of this superfamily, GlpT, which transports glycerol-3-phosphate into the cytoplasm and inorganic phosphate into the periplasm. The amino- and carboxyl-terminal halves of the protein exhibit a pseudo two-fold symmetry. Cl...

The Siah family of RING proteins function as ubiquitin ligase components, contributing to the degradation of multiple targets involved in cell growth, differentiation, angiogenesis, oncogenesis, and inflammation. Previously, a binding motif (degron) was recognized in many of the Siah degradation targets, suggesting that Siah itself may facilitate substrate recognition. We report the crystal str...

There is a high level of conservation tryptophans within the active site architecture cellulase family, whereas function four in catalytic domain Cel7A unclear. By mutating tryptophan residues from Penicillium piceum (PpCel7A), binding affinity between PpCel7A and p-nitrophenol-D-cellobioside (pNPC) was reduced as determined by Michaelis–Menten constants, molecular dynamics simulations, fluores...

The selectivity of serine proteinases action is mediated by high-specifice binding the proper parts protein substrate. Among such targets a special place belongs to areas functionally conditioned interaction with active center enzyme. Their sharp difference in enzyme affinity due synchronous and allosteric sites site specific amino acid residues substrate that are adequate specificity placed co...

Diphosphoinositol pentakisphosphate kinase 2 (PPIP5K2) is one of the mammalian PPIP5K isoforms responsible for synthesis of diphosphoinositol polyphosphates (inositol pyrophosphates; PP-InsPs), regulatory molecules that function at the interface of cell signaling and organismic homeostasis. The development of drugs that inhibit PPIP5K2 could have both experimental and therapeutic applications. ...

We describe the mapping and sequencing of mutations within the DNA polymerase gene of herpes simplex virus type 1 which confer resistance to aphidicolin, a DNA polymerase inhibitor. The mutations occur near two regions which are highly conserved among DNA polymerases related to the herpes simplex enzyme. They also occur near other herpes simplex mutations which affect the interactions between t...

GST (glutathione transferase) is a dimeric enzyme recognized for biotransformation of xenobiotics and endogenous toxic compounds. In the present study, residues forming the hydrophobic substrate-binding site (H-site) of a Delta class enzyme were investigated in detail for the first time by site-directed mutagenesis and crystallographic studies. Enzyme kinetics reveal that Tyr111 indirectly stab...

Selective control over Aβ production via γ-secretase modulators (GSM) is a promising strategy for treating Alzheimer's disease, yet the specific binding sites and mechanism of action GSMs remain unknown. Using recent cryo-electron microscopy structures substrate-bound we used two distinct methods to identify four potential pyridopyrazine-1,6-dione GSMs. We demonstrate site 4 formed between PS1-...

Insulin degrading enzyme (IDE) exists primarily as a dimer being unique among the zinc metalloproteases in that it exhibits allosteric kinetics with small synthetic peptide substrates. In addition the IDE reaction rate is increased by small peptides that bind to a distal site within the substrate binding site. We have generated mixed dimers of IDE in which one or both subunits contain mutations...