X-ray Structure of Gelatinase A Catalytic Domain Complexed with a Hydroxamate Inhibitor

Gelatinase A is a key enzyme in the family of matrix metalloproteinases (matrixins) that are involved in the degradation of the extracellular matrix. As this process is an integral part of tumour cell metastasis and angiogenesis, gelatinase is an important target for therapeutic intervention. The X-ray crystal structure of the gelatinase A catalytic domain (GaCD) complexed with batimastat (BB94), a hydroxamate inhibitor, shows an active site with a large S1\u27 specificity pocket. The structure is similar to previously solved structures of stromelysin catalytic domain (SCD) but with differences in VR1 and VR2, two surface-exposed loops on either side of the entrance to the active site. Comparison of GaCD with other members of the matrix metalloproteinase (MMP) family highlights the conservation of key secondary structural elements and the significant differences in the specificity pockets, knowledge of which should enhance our ability to design specific inhibitors for this important anticancer target

Crystal structures of 1:1 complexes of meclofenamic acid with choline and ethanolamine

The hydrated 1:1 complex of meclofenamic acid with choline crystallites in the orthorhombic acid space group P \bar{1} with a = 9.637(1), B = 12.962(5), C = 33.099(4) Å and Z = 8. Crystals of the corresponding anhydrous complex with ethanolamine are triclinic, space group Image , with a = 9.232(3), B = 12.287(5), C = 17.033(3) Å, \alpha = 70.21(2), \beta = 76.72(2), \gamma = 68.21(3)° and Z = 4. The structures have been solved by direct methods and refined to R value of 0.062 and 0.079, respectively for 1942 and 2852 observed reflections. The four crystallographically independent meclofenamate anions in the complexes have nearly the same molecular geometry which in turn is very similar to that found in the crystal structure of free meclofenamic acid. The choline and ethanolamine molecules assume a gauche conformation with respect to the central C---C bond. The invariant structural features observed in the crystals of the free fenamates are retained by the meclofenamate ions in the complexes. These features are the rigid coplanar geometry of the six-membered ring carrying the carboxyl group, the carboxyl group and the imino nitrogen atom, and the internal hydrogen bond connecting the imino and the carboxyl groups. The crystal structures are stabilised by ionic interactions between the carboxylate groups of meclofenamate ions and choline or ethanolamine cations, and hydrogen bonds. The choline complex exhibits pseudosymmetry and the distribution of molecules in it is nearly centrosymmetric although the space group is noncentrosymmetric. The packing of molecules in the crystals is such that the polar columns are surrounded by non-polar regions. The core of each column in the choline complex is made up of water molecules connected by hydrogen bonds involving disordered protons. The results of the X-ray structure analysis of fenamates and their crystalline complexes provide some insights into structure-function relationships in this family of drugs

Crystal structures of 1:1 complexes of meclofenamic acid with choline and ethanolamine

The hydrated 1:1 complex of meclofenamic acid with choline crystallites in the orthorhombic acid space group Pna2<SUB>1</SUB> with a = 9.637(1), b = 12.962(2), c = 33.099(4) Å and Z = 8 . Crystals of the corresponding anhydrous complex with ethanolamine are triclinic, space group P1̅, with a = 9.232(3), b = 12.287(5), c = 17.033(3) Å, α = 70.21(2), β = 76.72(2), γ = 68.21(3)° and Z = 4. The structures have been solved by direct methods and refined to R value of 0.062 and 0.079, respectively for 1942 and 2852 observed reflections. The four crystallographically independent meclofenamate anions in the complexes have nearly the same molecular geometry which in turn is very similar to that found in the crystal structure of free meclofenamic acid. The choline and ethanolamine molecules assume a gauche conformation with respect to the central C---C bond. The invariant structural features observed in the crystals of the free fenamates are retained by the meclofenamate ions in the complexes. These features are the rigid coplanar geometry of the six-membered ring carrying the carboxyl group, the carboxyl group and the imino nitrogen atom, and the internal hydrogen bond connecting the imino and the carboxyl groups. The crystal structures are stabilised by ionic interactions between the carboxylate groups of meclofenamate ions and choline or ethanolamine cations, and hydrogen bonds. The choline complex exhibits pseudosymmetry and the distribution of molecules in it is nearly centrosymmetric although the space group is noncentrosymmetric. The packing of molecules in the crystals is such that the polar columns are surrounded by non-polar regions. The core of each column in the choline complex is made up of water molecules connected by hydrogen bonds involving disordered protons. The results of the X-ray structure analysis of fenamates and their crystalline complexes provide some insights into structure-function relationships in this family of drugs

Preparation and x-ray characterization of four new crystal forms of Jacalin, a lectin from Artocarpus integrifolia

Four new crystal forms of the anti-T lectin from jackfruit (Artocarpus integrifolia) have been prepared and characterized. Three of them, two monoclinic (P21, A = 59·4 Å, B = 83·3 Å, C = 63·5 Å, β = 107·7°; C2, A = 106·1,Å, B = 53·9 Å, C = 128·0 Å, β = 95·0 Å) and one orthorhombic (C2221, A = 98·1 Å, B = 67·3 Å, C = 95·1 Å) were grown with 2-methylpentan-2,4-diol (MPD) as the precipitant while the fourth, an hexagonal from (P6122, A = b = 129·6 Å, C = 157·9 Å), was obtained in the presence of methyl-ga-Image -galactopyranoside with polyethylene glycol 4000 as the precipitant. The reported relative molecular mass (Mr) of the lectin was found to be inconsistent with the solvent content of the crystals estimated using measured densities. The Mr was redetermined using size-exclusion chromatography in the presence of methyl-α-Image -galactopyranoside and Ferguson-plot analysis of mobilities in polyacrylamide gel electrophoresis. The redetermined Mr (66,000) is consistent with the measured crystal densities. The orthorhombic and the hexagonal forms, which have one half molecule and one molecule, respectively, in the asymmetric unit, are suitable for high-resolution X-ray analysis

Preparation and X-ray characterization of four new crystal forms of jacalin, a lectin from Artocarpus integrifolia

Four new crystal forms of the anti-T lectin from jackfruit (Artocarpus integrifolia) have been prepared and characterized. Three of them, two monoclinic (P21, A = 59·4 Å, B = 83·3 Å, C = 63·5 Å, β = 107·7°; C2, A = 106·1,Å, B = 53·9 Å, C = 128·0 Å, β = 95·0 Å) and one orthorhombic (C2221, A = 98·1 Å, B = 67·3 Å, C = 95·1 Å) were grown with 2-methylpentan-2,4-diol (MPD) as the precipitant while the fourth, an hexagonal from (P6122, A = b = 129·6 Å, C = 157·9 Å), was obtained in the presence of methyl-ga-D-galactopyranoside with polyethylene glycol 4000 as the precipitant. The reported relative molecular mass (Mr) of the lectin was found to be inconsistent with the solvent content of the crystals estimated using measured densities. The Mr was redetermined using size-exclusion chromatography in the presence of methyl-α-D-galactopyranoside and Ferguson-plot analysis of mobilities in polyacrylamide gel electrophoresis. The redetermined Mr (66,000) is consistent with the measured crystal densities. The orthorhombic and the hexagonal forms, which have one half molecule and one molecule, respectively, in the asymmetric unit, are suitable for high-resolution X-ray analysis

A comparison of the diagnostic ability of vessel density and structural measurements of optical coherence tomography in primary open angle glaucoma.

PurposeTo compare the diagnostic abilities of vessel density measurements of the optic nerve head (ONH), peripapillary and macular regions on optical coherence tomography (OCT) angiography in eyes with primary open angle glaucoma (POAG) with that of the ONH rim area, peripapillary retinal nerve fiber layer (RNFL) thickness and the macular ganglion cell complex (GCC) thickness measurements.MethodsIn a cross sectional study, 78 eyes of 50 control subjects and 117 eyes of 67 POAG patients underwent vessel density and structural measurements with spectral domain OCT. POAG was diagnosed based on the masked evaluation of optic disc stereo photographs. Area under receiver operating characteristic curves (AUC) and sensitivities at fixed specificities of vessel densities in ONH, peripapillary and macular regions were compared with rim area, RNFL and GCC thickness.ResultsThe AUC (sensitivity at 95% specificity) of average vessel densities within the ONH, peripapillary and macular region were 0.77 (31%), 0.85 (56%) and 0.70 (18%) respectively. The same of ONH rim area, average RNFL and GCC thickness were 0.94 (83%), 0.95 (72%) and 0.93 (62%) respectively. AUCs of vessel densities were significantly lower (p&lt;0.05) than that of the corresponding structural measurements. Pre-treatment IOP (coefficient: 0.08) affected (p&lt;0.05) the AUC of ONH vessel density but not of any other vessel density or structural measurements.ConclusionsDiagnostic abilities of ONH, peripapillary and the macular vessel densities in POAG were significantly lower than ONH rim area, peripapillary RNFL and macular GCC measurements respectively. At fixed levels of glaucoma severity, the diagnostic ability of the ONH vessel density was significantly greater in eyes with higher pre-treatment IOP