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Inhibitor Binds (inhibitor + bind)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

A micromolar O-sulfated thiohydroximate inhibitor bound to plant myrosinase

ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 2 2010
Arthur Besle
The 1.6,Å resolution structure of the micromolar competitive inhibitor S -(N,N -dimethylaminoethyl) phenylacetothiohydroximate- O -sulfate bound to Sinapis alba myrosinase, a plant thioglucosidase, is reported. Myrosinase and its substrates, the glucosinolates, are part of the plant's defence system. The sulfate group and the phenyl group of the inhibitor bind to the aglycon-binding site of the enzyme, whereas the N,N -dimethyl group binds to the glucose-binding site and explains the large improvement in binding affinity compared with previous compounds. The structure suggests ways to increase the potency and specificity of the compound by improving the interactions with the hydrophobic pocket of the aglycon-binding site. [source]

Crystal structure of enoyl,acyl carrier protein reductase (FabK) from Streptococcus pneumoniae reveals the binding mode of an inhibitor

PROTEIN SCIENCE, Issue 4 2008
Jun Saito
Abstract Enoyl,acyl carrier protein (ACP) reductases are critical for bacterial type II fatty acid biosynthesis and thus are attractive targets for developing novel antibiotics. We determined the crystal structure of enoyl,ACP reductase (FabK) from Streptococcus pneumoniae at 1.7 Å resolution. There was one dimer per asymmetric unit. Each subunit formed a triose phosphate isomerase (TIM) barrel structure, and flavin mononucleotide (FMN) was bound as a cofactor in the active site. The overall structure was similar to the enoyl,ACP reductase (ER) of fungal fatty acid synthase and to 2-nitropropane dioxygenase (2-ND) from Pseudomonas aeruginosa, although there were some differences among these structures. We determined the crystal structure of FabK in complex with a phenylimidazole derivative inhibitor to envision the binding site interactions. The crystal structure reveals that the inhibitor binds to a hydrophobic pocket in the active site of FabK, and this is accompanied by induced-fit movements of two loop regions. The thiazole ring and part of the ureido moiety of the inhibitor are involved in a face-to-face ,,, stacking interaction with the isoalloxazine ring of FMN. The side-chain conformation of the proposed catalytic residue, His144, changes upon complex formation. Lineweaver,Burk plots indicate that the inhibitor binds competitively with respect to NADH, and uncompetitively with respect to crotonoyl coenzyme A. We propose that the primary basis of the inhibitory activity is competition with NADH for binding to FabK, which is the first step of the two-step ping-pong catalytic mechanism. [source]

The crystallographic structure of the aldose reductase,IDD552 complex shows direct proton donation from tyrosine 48

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 8 2004
Federico Ruiz
The X-ray crystal structure of human aldose reductase (ALR2) in complex with the inhibitor IDD552 was determined using crystals obtained from two crystallization conditions with different pH values (pH 5 and 8). In both structures the charged carboxylic head of the inhibitor binds to the active site, making hydrogen-bond interactions with His110 and Tyr48 and electrostatic interactions with NADP+. There is an important difference between the two structures: the observation of a double conformation of the carboxylic acid moiety of the inhibitor at pH 8, with one water molecule interacting with the main configuration. This is the first time that a water molecule has been observed deep inside the ALR2 active site. Furthermore, in the configuration with the lower occupancy factor the difference electron-density map shows a clear peak (2.5,) for the H atom in the hydrogen bond between the inhibitor's carboxylic acid and the Tyr48 side-chain O atom. The position of this peak implies that this H atom is shared between both O atoms, indicating possible direct proton transfer from this residue to the inhibitor. This fact agrees with the model of the catalytic mechanism, in which the proton is donated by the Tyr48 hydroxyl to the substrate. These observations are useful both in drug design and in understanding the ALR2 mechanism. [source]

Structure of the complex of porcine pancreatic elastase with a trimacrocyclic peptide inhibitor FR901451

ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2005
Takayoshi Kinoshita
Porcine pancreatic elastase (PPE) resembles the attractive drug target leukocyte elastase, which has the ability to degrade connective tissue in the body. The crystal structure of PPE complexed with a novel trimacrocyclic peptide inhibitor, FR901451, was solved at 1.9,Å resolution. The inhibitor occupied the subsites S3 through S3, of PPE and induced conformational changes in the side chains of Arg64 and Arg226, which are located at the edges of the substrate-binding cleft. Structural comparison of five PPE,inhibitor complexes, including the FR901451 complex and non-ligated PPE, reveals that the residues forming the S2, S1, S1, and S2, subsites in the cleft are rigid, but the two arginine residues playing a part in the S3 and S3, subsites are flexible. Structural comparison of PPE with human leukocyte elastase (HLE) implies that the inhibitor binds to HLE in a similar manner to the FR901451,PPE complex. This structural insight may help in the design of potent elastase inhibitors. [source]