In vitro and in silico investigations of the binding interactions between chlorophenols and trypsin.

Being the first-degree toxic pollutants, chlorophenols (CP) have potential carcinogenic and mutagenic activity and toxicity. Since there still lacks studies on molecular interactions of chlorophenols with trypsin, one major binding target of many exogenous environmental pollutants, the binding interactions between five chlorophenols, 2-CP, 2,6-DCP, 2,4,6-TCP, 2,4,6-TCP, 2,3,4,6-TCP and PCP and trypsin were characterized by the combination of multispectroscopic techniques and molecular modeling. The chlorophenols bind at the one main site of trypsin and the binding induces the changes of microenvironment and global conformations of trypsin. Different number of chloride atoms significantly affects the binding and the binding constants KA ranks as KA (2-CP) < KA (2,6-DCP) ≈ KA (2,4,6-TCP) < KA (2,3,4,6-TCP) < KA (PCP). These chlorophenols interacts with trypsin mainly through hydrophobic interactions and via hydrogen bonding interactions and aromatic-aromatic π-π stacking interaction. Our results offer insights into the binding mechanism of chlorophenols with trypsin and provide important information for possible toxicity risk of chlorophenols to human health.

A one-dimensional coordination polymer with a three-dimensional supramolecular framework: catena-poly[[[(3,4,7,8-tetramethyl-1,10-phenanthroline)cadmium(II)]-µ3-4,4'-sulfonyldibenzoato] trihydrate].

In the title mixed-ligand metal-organic polymeric compound, {[Cd(C14H8O6S)(C16H16N2)]·3H2O}n, the asymmetric unit contains a crystallographically unique Cd(II) atom, one doubly deprotonated 4,4'-sulfonyldibenzoic acid (H2SDBA) ligand, one 3,4,7,8-tetramethyl-1,10-phenanthroline (TMPHEN) molecule and three solvent water molecules. Each Cd(II) centre is six-coordinated by two O atoms from a chelating carboxylate group of a SDBA(2-) ligand, two O atoms from monodentate carboxylate groups of two different SDBA(2-) ligands and two N atoms from a chelating TMPHEN ligand. There are two coordination patterns for the carboxylate groups of the SDBA(2-) ligand, with one in a µ1-η(1):η(1) chelating mode and the other in a µ2-η(1):η(1) bis-monodentate mode. Single-crystal X-ray diffraction analysis revealed that the title compound is a one-dimensional double-chain polymer containing 28-membered rings based on the [Cd2(CO2)2] rhomboid subunit. More interestingly, a chair-shaped water hexamer cluster is observed in the compound.

A fivefold interpenetrating diamond-like three-dimensional metal-organic framework: poly[(µ2-benzene-1,4-diacetato)[µ2-1,6-bis(1,2,4-triazol-1-yl)hexane]zinc(II)].

In the mixed-ligand metal-organic title polymeric compound, [Zn(C(10)H(8)O(4))(C(10)H(16)N(6))](n) or [Zn(PBEA)(BTH)](n) [H(2)PBEA is benzene-1,4-diacetic acid and BTH is 1,6-bis(1,2,4-triazol-1-yl)hexane], the asymmetric unit contains a Zn(II) atom, one half of a BTH ligand and one half of a doubly deprotonated H(2)PBEA ligand. Each Zn(II) centre lies on a crystallographic twofold rotation axis and is four-coordinated by two O atoms from two distinct PBEA(2-) ligands and two N atoms from two different BTH ligands in a {ZnO(2)N(2)} coordination environment. The three-dimensional topology of the title compound corresponds to that of a fivefold interpenetrating diamond-like metal-organic framework.