Polymeric architectures of bismuth citrate based on dimeric building blocks.

Unlabelled: Four bismuth complexes, (HEn)[Bi(cit)(HO)]·(HO) (), (HEn)[Bi(cit)Cl]·(HO) (), (HPy)[Bi(cit)(HO)]·(HO) () and (HEn)[Bi(cit)](HO) () [cit = citrate; En = ethylenediamine; Py = pyridine] have been synthesized and crystallized. The crystal structures reveal that the basic building blocks in all of these complexes are bismuth citrate dimeric units which combine to form polymeric architectures. The embedded protonated ethylenediamine and pyridine moieties in the polymeric frameworks have been identified by X-ray crystallography and solid-state cross polarization/magic angle spinning (CP/MAS) C NMR.

Refolding and kinetic characterization of the phosphodiesterase-8A catalytic domain.

Cyclic nucleotide phosphodiesterase-8 (PDE8) hydrolyzes the second messenger cAMP and is involved in many biological processes such as testosterone production. Although the bacterial and mammalian expression systems have been extensively tried, production of large quantity of soluble and active PDE8 remains to be a major hurdle for pharmacological and structural studies. Reported here is a detailed protocol of refolding and purification of large quantity of the PDE8A1 catalytic domain (residues 480-820) and kinetic characterization of the refolded protein.

Kinetic and structural studies of phosphodiesterase-8A and implication on the inhibitor selectivity.

Cyclic nucleotide phosphodiesterase-8 (PDE8) is a family of cAMP-specific enzymes and plays important roles in many biological processes, including T-cell activation, testosterone production, adrenocortical hyperplasia, and thyroid function. However, no PDE8 selective inhibitors are available for trial treatment of human diseases. Here we report kinetic properties of the highly active PDE8A1 catalytic domain prepared from refolding and its crystal structures in the unliganded and 3-isobutyl-1-methylxanthine (IBMX) bound forms at 1.

1H and 13C NMR assignments of two new diaryl ethers phomopsides A and B from the mangrove endophytic fungus (ZZF08).

Two new diaryl ethers, named phomopside A (1) and B (2), together with known excelsione (3) were isolated from the mangrove endophytic fungus Phomopsis sp. (ZZF08) obtained from the South China Sea coast. The structure of 1 was elucidated by NMR spectroscopy and confirmed by X-ray crystallography.

An insight into the pharmacophores of phosphodiesterase-5 inhibitors from synthetic and crystal structural studies.

Selective inhibitors of cyclic nucleotide phosphodiesterase-5 (PDE5) have been used as drugs for treatment of male erectile dysfunction and pulmonary hypertension. An insight into the pharmacophores of PDE5 inhibitors is essential for development of second generation of PDE5 inhibitors, but has not been completely illustrated. Here we report the synthesis of a new class of the sildenafil derivatives and a crystal structure of the PDE5 catalytic domain in complex with 5-(2-ethoxy-5-(sulfamoyl)-3-thienyl)-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one (12).

Structures of the four subfamilies of phosphodiesterase-4 provide insight into the selectivity of their inhibitors.

PDE4 (phosphodiesterase-4)-selective inhibitors have attracted much attention as potential therapeutics for the treatment of both depression and major inflammatory diseases, but their practical application has been compromised by side effects. A possible cause for the side effects is that current PDE4-selective inhibitors similarly inhibit isoforms from all four PDE4 subfamilies. The development of PDE4 subfamily-selective inhibitors has been hampered by a lack of structural information.

Crystal structure of a cyclomaltoheptaose-4-hydroxybiphenyl inclusion complex.

The crystal structure of the inclusion complex of cyclomaltoheptaose (beta-cyclodextrin) with 4-hydroxybiphenyl was determined by single-crystal X-ray diffraction at 150K. The complex contains two cyclomaltoheptaose molecules, two 4-hydroxybiphenyl molecules, one ethanol molecule and fifteen water molecules in the asymmetric unit, and could be formulated as [2(C(42)H(70)O(35)).2(C(12)H(10)O).

The crystal structure of the 1:1 inclusion complex of beta-cyclodextrin with benzamide.

The 1:1 inclusion complex of beta-cyclodextrin and benzamide was prepared and characterized by single crystal X-ray diffraction, PXRD, TGA, and IR. This complex crystallizes in the monoclinic P2(1) space group with unit cell constants a=15.4244(16), b=10.

Multiple conformations of phosphodiesterase-5: implications for enzyme function and drug development.

Phosphodiesterase-5 (PDE5) is the target for sildenafil, vardenafil, and tadalafil, which are drugs for treatment of erectile dysfunction and pulmonary hypertension. We report here the crystal structures of a fully active catalytic domain of unliganded PDE5A1 and its complexes with sildenafil or icarisid II. These structures together with the PDE5A1-isobutyl-1-methylxanthine complex show that the H-loop (residues 660-683) at the active site of PDE5A1 has four different conformations and migrates 7-35A upon inhibitor binding.

Synthesis of elliptical vanadoborates housing bimetallic centers [Zn4(B2O4H2)(V10B28O74H8)]8- and [Mn4(C2O4)(V10B28O74H8)]10-.

The hydrothermal synthesis of three new vanadoborate compounds with elliptical (V10B28O74H8) clusters is described. The clusters contain pairs of bimetallic Zn2 or Mn2 units.

Reversible and selective amine interactions of [Cd(mu2-N,O-p-NH2C6H4SO3)2(H2O)2]n.

[Cd(mu2-N,O-p-NH2C6H4SO3)2(H2O)2]n (1) is a layered coordination compound. The solid-vapor reactions between crystalline 1 and a series of volatile amines were investigated and the corresponding amine adducts were characterized by EA, TGA, PXRD and IR. Among them, the C2H5NH2 and C3H7NH2 adducts, namely [Cd(C2H5NH2)4(H2O)2](H2NC6H4SO3)2 (3) and [Cd(C3H7NH2)4(O-p-H2NC6H4SO3)2].

Variation in the coordination mode of arenedisulfonates: syntheses and structural characterization of mononuclear and dinuclear cadmium(II) arenedisulfonate complexes with two- to zero-dimensional architectures.

Seven cadmium(II) arenedisulfonate compounds, namely [Cd(2,2'-bpy)(2)(H(2)O)(peds)].4H(2)O (1), [Cd(2)(2,2'-bpy)(4)(H(2)O)(2)(1,5nds)](1,5nds).4H(2)O (2), [Cd(cyclam)(1,5nds)](2) (3), ([Cd(inia)(2)(H(2)O)(2)(2,6nds)].

Di-mu-chloro-bis([2-[N,N-bis(2-aminoethyl)amino-kappa3N]ethylaminium]-copper(II)) bis(naphthalene-1,5-disulfonate) pentahydrate.

The title compound, [Cu2(C6H19N4)2Cl2](C10H6O6S2)2*5H2O, is comprised of discrete [Cu2(tren)2Cl2]2+ dimers [tren is 2-[N,N-bis(2-aminoethyl)amino]ethylaminium] and naphthalene-1,5-disulfonate anions. Two Cl- anions bridge two Cu(II) ions, each of which is also coordinated by two of the primary and the tertiary amino N atoms of the tren ligand, giving each metal atom a distorted square-pyramidal coordination geometry. The cation lies about an inversion centre and the asymmetric unit also has two independent anions lying about inversion centres.

Clathration of Two-Dimensional Coordination Polymers: Synthesis and Structures of [M(4,4'-bpy)(2)(H(2)O)(2)](ClO(4))(2).(2,4'-bpy)(2).H(2)O and [Cu(4,4'-bpy)(2)(H(2)O)(2)](ClO(4))(4).(4,4'-H(2)Bpy) (M = Cd(II), Zn(II) and bpy = Bipyridine).

In the presence of guest 2,4'-bpy molecules or under acidic conditions, three compounds, [Cd(4,4'-bpy)(2)(H(2)O)(2)](ClO(4))(2).(2,4'-bpy)(2).H(2)O (1), [Zn(4,4'-bpy)(2)(H(2)O)(2)](ClO(4))(2).