Shandong Nonmetallic Material Institute

Jinan Shandong, China

Shandong Nonmetallic Material Institute

Jinan Shandong, China
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Hou Q.,Shandong University | Hou Q.,Shandong Nonmetallic Material Institute | Sheng X.,Shandong University | Liu Y.,Shandong University | Liu Y.,CAS Northwest Institute of Plateau Biology
Physical Chemistry Chemical Physics | Year: 2014

Archaeal fructose-1,6-bisphosphate aldolase/phosphatase (FBPA/P) is a newly identified unusual bifunctional enzyme (Nature, 2010, 464, 1077), which contains one single catalytic domain but catalyzes two chemically distinct reactions of gluconeogenesis. It is different from the ordinary enzymes whose active sites are responsible for a specific reaction. To explore the catalytic characteristic of FBPA/P, the aldol condensation mechanism of bifunctional FBPA/P has been investigated using quantum mechanics/molecular mechanics (QM/MM) method. The whole reaction process can be divided into two half-reactions involving seven elementary steps. A Schiff base intermediate is theoretically confirmed, agreeing well with the recently resolved crystal structures (Nature, 2011, 478, 538). The free energy barrier of the rate-limiting step is calculated to be 22.2 kcal mol-1, which is a concerted process of a nucleophilic attack by the enolic carbon to the ketonic carbon and a proton transfer from Tyr229 to the ketonic oxygen. Lys232 plays an important role in forming a Schiff base intermediate with the substrate (DHAP). Tyr229 functions as a proton shuttle during the catalysis. This is the first theoretical study on the aldol condensation mechanism of FBPA/P, which may provide useful information for understanding bifunctional enzymes. © 2014 the Partner Organisations.


Wei H.,Shandong Nonmetallic Material Institute | Wang Q.,Shandong Nonmetallic Material Institute | Chen G.,Shandong Nonmetallic Material Institute | Fan W.,Shandong University | And 5 more authors.
Fuhe Cailiao Xuebao/Acta Materiae Compositae Sinica | Year: 2015

Carbon nanotubes (CNTs) were prepared directly on carbon fibers by chemical vapor deposition (CVD) method. The different process parameters such as catalyst, deposition temperature, hydrogen flow rate and distance between samples and intake were investigated in relation to morphology and structure. The samples were characterized and analyzed by SEM and high resolution transmission electron microscopy (HRTEM). Results show that CNTs in-situ grown on surface of CF is multi-wall structure. CNTs which grow on carbon fibers surface using Ni-catalyst are thin and uniform distribution. The diameter and length of CNTs using Fe-catalyst reduce and yield decrease when the deposition temperature rises from 600℃ to 750℃. The diameter and length of CNTs raise with hydrogen flow rate increasing. It is in favor of preparing high quality CNTs at 30 cm from fibers to intake, at which CNTs densely distribute on the carbon fiber surface and their diameter are uniform. © 2015, BUAA Culture Media Group Ltd.. All right reserved.


Zhang W.-S.,Shandong Nonmetallic Material Institute | Liu Z.-J.,Shandong Nonmetallic Material Institute | Xu F.,Shandong Nonmetallic Material Institute | Xun Q.-N.,Shandong Nonmetallic Material Institute
Acta Crystallographica Section E: Structure Reports Online | Year: 2011

In the title compound, [HgBr2(C13H 11NO)2], the HgII atom adopts a four-coordinated HgN2Br2 geometry, formed by two pyridine N atoms from two ligands and two bromide anions. The complex is located on a twofold axis. The coordination geometry is close to forming a see-saw (SS-4) polyhedron, the symmetry-related organic ligands being almost perpendicular; the dihedral angles between the two pyridine rings and between the two benzene rings are 85.5 (4) and 87.7 (4)°, respectively. Within the organic ligand, the pyridine ring is nearly coplanar with the benzene ring [dihedral angle = 13.1 (8)°]. In the crystal, the molecular complexes are connected through weak intermolecular C-H⋯Br contacts.


PubMed | Shandong Nonmetallic Material Institute
Type: Journal Article | Journal: Acta crystallographica. Section E, Structure reports online | Year: 2011

In the title compound, [HgBr(2)(C(13)H(11)NO)(2)], the Hg(II) atom adopts a four-coordinated HgN(2)Br(2) geometry, formed by two pyridine N atoms from two ligands and two bromide anions. The complex is located on a twofold axis. The coordination geometry is close to forming a see-saw (SS-4) polyhedron, the symmetry-related organic ligands being almost perpendicular; the dihedral angles between the two pyridine rings and between the two benzene rings are 85.5(4) and 87.7(4), respectively. Within the organic ligand, the pyridine ring is nearly coplanar with the benzene ring [dihedral angle = 13.1(8)]. In the crystal, the mol-ecular complexes are connected through weak inter-molecular C-HBr contacts.

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