Fragment hopping, a new fragment-based approach for de novo inhibitor design focusing on ligand diversity and isozyme selectivity, is described. The core of this the derivation minimal pharmacophoric element each pharmacophore. Sites both binding selectivity are considered in deriving elements. Five general-purpose libraries established: basic fragment library, bioisostere rules metabolic stability, toxicophore side chain library. These employed to generate focused match elements...

Heme-regulated eukaryotic initiation factor 2alpha (eIF2alpha) kinase (HRI) functions in response to the heme iron concentration. At appropriate concentrations under normal conditions, HRI function is suppressed by binding of iron. Conversely, upon shortage, autophosphorylates and subsequently phosphorylates substrate, eIF2alpha, leading termination protein synthesis. The molecular mechanism sensing HRI, including identification specific site, remains be established. In present study we...

To design a new class of selective neuronal nitric oxide synthase (NOS) inhibitors, and demonstrate that administration in rabbit model for cerebral palsy (CP) prevents hypoxia-ischemia-induced deaths reduces the number newborn kits exhibiting signs CP.We used novel computer-based drug method called fragment hopping to identify chemical entities, synthesized them, conducted vitro enzyme inhibition studies with three isozymes NOS vivo experiments monitor cardiovascular effects on pregnant...

YddV from Escherichia coli (Ec) is a novel globin-coupled heme-based oxygen sensor protein displaying diguanylate cyclase activity in response to availability. In this study, we quantified the turnover numbers of active [Fe(III), 0.066 min−1; Fe(II)−O2 and Fe(II)−CO, 0.022 min−1] Fe(III)−protoporphyrin IX complex; Fe(II), Fe(II)−protoporphyrin complex] inactive forms [Fe(II) Fe(II)−NO, <0.01 for first time. Our data indicate that reaction rate-determining step two consecutive reactions...

Sphingosine 1-phosphate (S1P) is a serum-borne naturally occurring sphingolipid, specifically enriched in high-density lipoprotein (HDL) fractions. S1P binds to G-protein-coupled S1P1 receptors activate endothelial NO synthase (eNOS) vascular cells. We explored whether and how statins, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, modulate expression of responses for subsequent stimulation with or HDL.Protein phosphorylation mRNA cultured bovine aortic cells (BAEC)...

Two-component signal transduction systems regulate numerous important physiological functions in bacteria. In this study we have identified, cloned, overexpressed, and characterized a dimeric full-length heme-bound (heme:protein, 1:1 stoichiometry) globin-coupled histidine kinase (AfGcHK) from Anaeromyxobacter sp. strain Fw109-5 for the first time. The Fe(III), Fe(II)-O2, Fe(II)-CO complexes of protein displayed autophosphorylation activity, whereas Fe(II) complex had no significant...

Heme-regulated eukaryotic initiation factor 2α kinase (HRI) regulates the synthesis of hemoglobin in reticulocytes response to heme availability. HRI contains a tightly bound at N-terminal domain. Earlier reports show that nitric oxide (NO) catalysis. However, mechanism this process remains unclear. In present study, we utilize vitro assays, optical absorption, electron spin resonance (ESR), and Raman spectra purified full-length for first time elucidate regulation NO. was activated via upon...

The role of nitric oxide (NO) in myocardial ischemia-reperfusion injury is still controversial. To determine the NO propagation a coronary artery occlusion-reperfusion model, we examined effect competitive synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), with and without L-arginine, on size infarct resulting from occlusion (30 min) followed by reperfusion (48 hr) rabbits. L-NAME (300 micrograms/kg, as bolus, 100 micrograms/kg/min, i.v.) L-arginine mg/kg, 10 mg/kg/min, was...

Heme-regulated eIF2α kinase [heme-regulated inhibitor (HRI)] plays a critical role in the regulation of protein synthesis by heme iron. The active site is located C-terminal domain, whereas N-terminal domain suggested to regulate catalysis response binding. Here, we found that rate dissociation for Fe(III)−protoporphyrin IX was much higher full-length HRI (1.5 × 10-3 s-1) than myoglobin (8.4 10-7 or α-subunit hemoglobin (7.1 10-6 s-1), demonstrating heme-sensing character HRI. Because...

Neuronal PAS protein 2 (NPAS2), a heme-binding transcriptional regulatory factor, is involved in circadian rhythms. Period homologue (Per) another important factor that binds to cryptochrome (Cry). The resultant Per/Cry heterodimer interacts with the NPAS2/BMAL1 inhibit transcription of Per and Cry. Previous cell biology experiments indicate mouse Per2 (mPer2) also protein, heme shuttling between mPer2 NPAS2 may regulate transcription. In present study, we show isolated PAS-A domain...

Magnetic impurities coupled antiferromagnetically to a one-dimensional Heisenberg model are studied by numerical diagonalization of chains finite clusters. By calculating the binding energy and correlation function, it is shown that local singlet develops around each impurity. This holds true for systems with single impurity, two impurities, forming lattice. The character found be little affected presence other impurity spins. A small effective interaction between pair spins, which...

SOUL is specifically expressed in the retina and pineal gland displays more than 40% sequence homology with p22HBP, a heme protein ubiquitously numerous tissues. was purified as dimer absence of from Escherichia coli expression system but displayed hexameric structure upon binding. Heme-bound optical absorption resonance Raman spectra typical 6-coordinate low-spin protein, one per monomeric unit for both Fe(III) Fe(II) complexes. Spectral data additionally suggest that axial ligands complex...

The dynamics of an impurity spin that couples to a two-dimensional system strongly correlated electrons is studied. They give rise fluctuating exchange field acting on the spin. We assume fluctuations can be treated as Gauss-Markoff process. First case considered where are described by Heisenberg Hamiltonian. stochastic equation solved for spectral function impurity-spin correlation both cases, i.e., slow and fast fluctuation field. solution generalized quantum mechanical relating it...

The heme-regulated phosphodiesterase, Ec DOS, is a redox sensor that uses the heme in its PAS domain to regulate catalysis. rate of O2 association (kon) with full-length DOS extremely slow at 0.0019 μm–1 s–1, compared >9.5 s–1 for 6-coordinated globin-type hemoproteins, as determined by stopped-flow method. This dramatically increased (up 16-fold) isolated heme-bound domain. Dissociation constants (Kd) calculated from kinetic parameters are 340 and 20 μm wild-type enzyme domain,...

The catalytic activity of heme-regulated phosphodiesterase from Escherichia coli (Ec DOS) on cyclic di-GMP is markedly enhanced upon binding gas molecules, such as O2 and CO, to the heme iron complex in sensor domain. Arg97 interacts directly with bound Fe(II) crystal structure isolated heme-bound domain PAS DOS-PAS) may thus be critical ligand recognition. To establish specific role Arg97, we generated Arg97Ala, Arg97Glu, Arg97Ile mutant Ec DOS-PAS proteins examined O2, cyanide, well redox...

Neuronal PAS domain protein 2 (NPAS2) is a circadian rhythm-associated transcription factor with two heme-binding sites on domains. In the present study, we compared optical absorption spectra, resonance Raman kinetics and DNA-binding characteristics of isolated fragment containing N-terminal basic helix-loop-helix (bHLH) first (PAS-A) NPAS2 those PAS-A alone. We found that heme-bound bHLH-PAS-A mainly exists as dimer in solution. The Soret peak Fe(III) complex for (421 nm) was located at...

We report on the Cu 1s resonant inelastic X-ray scattering (RIXS) of Cu-O one-dimensional (1D) strongly correlated insulator systems with contrasting atomic arrangements, namely edge-sharing CuGeO3 and corner-sharing Sr2CuO3. Owing to good statistics high-resolution RIXS data, so far unresolved fine structures are revealed. Detailed photon-energy momentum dependence spectra in comparison theoretical calculations has clarified natures low-energy charge excitations hybridization electronic states.

The neuronal isoform of nitric oxide synthase (nNOS), the enzyme responsible for production in central nervous system, represents an attractive target treatment various neurodegenerative disorders. X-ray crystal structures complexes nNOS with two nNOS-selective inhibitors, (4S)-N-{4-amino-5-[(2-aminoethylamino]pentyl}-N‘-nitroguanidine (1) and 4-N-(Nω-nitro-l-argininyl)-trans-4-amino-l-proline amide (2), led to discovery a conserved structural water molecule that was hydrogen bonded between...

We calculate the direct and inverse photoemission spectra of 3d transition metals with fcc or bcc structure. The dynamics d electrons is described by an extended Hubbard model including five canonical bands in one-particle operator ${\mathit{H}}_{0}$ all relevant on-site Coulomb exchange matrix elements interaction Hamiltonian ${\mathit{H}}_{1}$. For ground state a quantum-chemical ansatz made taking local spin density correlations into account. retarded Green's functions are evaluated using...