Pseudomonas aeruginosa (P. aeruginosa) is a common opportunistic human pathogen that can lead to severe diseases in immunocompromised patients. The insulin-cleaving membrane protease (ICMP) of P. aeruginosa plays a vi...Pseudomonas aeruginosa (P. aeruginosa) is a common opportunistic human pathogen that can lead to severe diseases in immunocompromised patients. The insulin-cleaving membrane protease (ICMP) of P. aeruginosa plays a vital role in the pathogenesis of the bacterium and is therefore characterized as an important bacterial virulence factor. In addition, ICMP also serves as a founding member of the M75 peptidase family and represents a prototype of the imelysin/imelysin-like proteins. Despite of its functional importance in the pathogenesis of P. aeruginosa and of a root position as the prototypic imelysin/imelysin-like member, the structural features of the protein remain uninvestigated. Since preparation of homogeneous and crystallizable protein species is the prerequisite for structural studies by crystallography, we reported the successful expression, purification, and crystallization of P. aeruginosa ICMP in this study. The protein was over-expressed in Escherichia coli as a GST-fusion protein, cleaved to remove the fusion tag, and then purified to homogeneity. Diffractable crystals were obtained using the sitting-drop vapour-diffusion method. The crystals diffracted to 2.5 Å?resolution and belonged to space group P212121, with unit-cell parameters a = 54.47, b = 158.98, c = 162.84 Å, α = β = γ = 90°. Preliminary analysis of the diffraction data revealed high-quality crystallographic statistics with a Matthews coefficient of about 2.61 Å3.Da-1 and a solvent content of about 52.58%, indicating the presence of three ICMP molecules in the asymmetric unit. The current work therefore paved the way for future studies aiming to delineate the characteristics of ICMP at the atomic level.展开更多
THE phycobilisomes in blue-green algae and red algae are the functional units which absorb and transfer light energy. These supramolecular aggregates are attached on the outer surface of the thylakoid or photosyntheti...THE phycobilisomes in blue-green algae and red algae are the functional units which absorb and transfer light energy. These supramolecular aggregates are attached on the outer surface of the thylakoid or photosynthetic membrane. Phycobilisomes absorb light in the range of 450—650 nm with an overall quantum efficiency of almost 100%, Electron microscopic studies showed that phycobilisomes consist of two distinct structure parts: the core and the rods.展开更多
A new diterpene with an abietane skeleton, 3β-hydroxy-8α,14α-epoxyabieta-11,13(15)- dien-16,12-olide, was isolated from the root of Suregada glomerulate(Blume) Baill. Its structure was elucidated on the basis of sp...A new diterpene with an abietane skeleton, 3β-hydroxy-8α,14α-epoxyabieta-11,13(15)- dien-16,12-olide, was isolated from the root of Suregada glomerulate(Blume) Baill. Its structure was elucidated on the basis of spectroscopic and X-ray crystallographic analysis.展开更多
Two series, totalizing twelve, of new compounds, ethyl 1-aroyl/aroylmethyl-5-methyl-3- methylthiopyrazole-4-carboxylates 5/6, have been synthesized via highly regioselective acylation and alkylation of ethyl 3-methyl-...Two series, totalizing twelve, of new compounds, ethyl 1-aroyl/aroylmethyl-5-methyl-3- methylthiopyrazole-4-carboxylates 5/6, have been synthesized via highly regioselective acylation and alkylation of ethyl 3-methyl-5-methylthio-1H- pyrazole-4-carboxylate 2a with aroyl chloride 3 and alpha-tosyloxysubstitutedacetophenones 4. Unexpected structures of the product have been unambiguously determined by both X-ray crystallographic analysis and 2D NMR.展开更多
The Preparation of 9-Methyl-3-thiophen-2-yl-thieno [3, 2-e] [1, 2, 4] triazolo [4, 3-c] pyrimi-dine-8-carboxylic acid ethyl ester is described. Elemental analysis, IR spectrum, 1H NMR, 13C NMR and X-ray crystal struct...The Preparation of 9-Methyl-3-thiophen-2-yl-thieno [3, 2-e] [1, 2, 4] triazolo [4, 3-c] pyrimi-dine-8-carboxylic acid ethyl ester is described. Elemental analysis, IR spectrum, 1H NMR, 13C NMR and X-ray crystal structure analyses were carried out to determine the composition and molecular structure of the title compound. There are two independent molecules in the asymmetric unit exhibiting intermolecular C-H…N, C-H…O interactions with additional π-π interaction that further helps in stabilizing the supramolecular structure. The results showed that the proposed method for synthesis is simple, precise and accurate which was further confirmed by crystal structure analysis.展开更多
1,4-anhydro-2-trifiyl-3,5-O-benzenylidene-L-xylitol (5) was constructed in six steps from protected D-xylose. Substitution of 5 with protected 8-bromoinosine 6 gave the key intermediate 5 ' -O-TBS-2 ' ,3 '...1,4-anhydro-2-trifiyl-3,5-O-benzenylidene-L-xylitol (5) was constructed in six steps from protected D-xylose. Substitution of 5 with protected 8-bromoinosine 6 gave the key intermediate 5 ' -O-TBS-2 ' ,3 ' -di-O-acctyl-N-1-(2 ' -deoxy-1 ' ,4 ' -anhydro-3 ' ,5 ' -O-benzenylidene (14). Selective removal of 5 ' -O-TBS-group gave the corresponding though phosphorylation which was characterized by X-ray crystallographical analysis.展开更多
Thiazine sugar derivative 2 was synthesized and characterized by IR, NMR and H RMS, and its crystal structure was determined by X-ray diffraction analysis. The crystal is of monoclinic system （C16H24N2O8S2, Mr = 436...Thiazine sugar derivative 2 was synthesized and characterized by IR, NMR and H RMS, and its crystal structure was determined by X-ray diffraction analysis. The crystal is of monoclinic system （C16H24N2O8S2, Mr = 436.49） with space group P21, a = 10.311（2）, b = 9.1198（18）, c = 11.623（2）A, β = 109.47（3）°, V= 1030.4（4）A^3, Z= 2, Dc = 1.407 g/cm^3, F（000）= 460, μ= 0.303 mm^-1, the final R = 0.0437 and wR = 0.0561 for 1954 observed reflections （I 〉 2σ（I））. Nine hydrogen bonds were found. The absolute configuration of this molecule was confirmed by comparison with the original material.展开更多
文摘Pseudomonas aeruginosa (P. aeruginosa) is a common opportunistic human pathogen that can lead to severe diseases in immunocompromised patients. The insulin-cleaving membrane protease (ICMP) of P. aeruginosa plays a vital role in the pathogenesis of the bacterium and is therefore characterized as an important bacterial virulence factor. In addition, ICMP also serves as a founding member of the M75 peptidase family and represents a prototype of the imelysin/imelysin-like proteins. Despite of its functional importance in the pathogenesis of P. aeruginosa and of a root position as the prototypic imelysin/imelysin-like member, the structural features of the protein remain uninvestigated. Since preparation of homogeneous and crystallizable protein species is the prerequisite for structural studies by crystallography, we reported the successful expression, purification, and crystallization of P. aeruginosa ICMP in this study. The protein was over-expressed in Escherichia coli as a GST-fusion protein, cleaved to remove the fusion tag, and then purified to homogeneity. Diffractable crystals were obtained using the sitting-drop vapour-diffusion method. The crystals diffracted to 2.5 Å?resolution and belonged to space group P212121, with unit-cell parameters a = 54.47, b = 158.98, c = 162.84 Å, α = β = γ = 90°. Preliminary analysis of the diffraction data revealed high-quality crystallographic statistics with a Matthews coefficient of about 2.61 Å3.Da-1 and a solvent content of about 52.58%, indicating the presence of three ICMP molecules in the asymmetric unit. The current work therefore paved the way for future studies aiming to delineate the characteristics of ICMP at the atomic level.
文摘THE phycobilisomes in blue-green algae and red algae are the functional units which absorb and transfer light energy. These supramolecular aggregates are attached on the outer surface of the thylakoid or photosynthetic membrane. Phycobilisomes absorb light in the range of 450—650 nm with an overall quantum efficiency of almost 100%, Electron microscopic studies showed that phycobilisomes consist of two distinct structure parts: the core and the rods.
基金the Natural Science Foundation of Beijing(No.2042020)for support of this research
文摘A new diterpene with an abietane skeleton, 3β-hydroxy-8α,14α-epoxyabieta-11,13(15)- dien-16,12-olide, was isolated from the root of Suregada glomerulate(Blume) Baill. Its structure was elucidated on the basis of spectroscopic and X-ray crystallographic analysis.
基金The project was supported by the Natural Science Foundation of Shandong Province(No.Y2003B01)NNSFC(No.20172031.
文摘Two series, totalizing twelve, of new compounds, ethyl 1-aroyl/aroylmethyl-5-methyl-3- methylthiopyrazole-4-carboxylates 5/6, have been synthesized via highly regioselective acylation and alkylation of ethyl 3-methyl-5-methylthio-1H- pyrazole-4-carboxylate 2a with aroyl chloride 3 and alpha-tosyloxysubstitutedacetophenones 4. Unexpected structures of the product have been unambiguously determined by both X-ray crystallographic analysis and 2D NMR.
文摘The Preparation of 9-Methyl-3-thiophen-2-yl-thieno [3, 2-e] [1, 2, 4] triazolo [4, 3-c] pyrimi-dine-8-carboxylic acid ethyl ester is described. Elemental analysis, IR spectrum, 1H NMR, 13C NMR and X-ray crystal structure analyses were carried out to determine the composition and molecular structure of the title compound. There are two independent molecules in the asymmetric unit exhibiting intermolecular C-H…N, C-H…O interactions with additional π-π interaction that further helps in stabilizing the supramolecular structure. The results showed that the proposed method for synthesis is simple, precise and accurate which was further confirmed by crystal structure analysis.
文摘1,4-anhydro-2-trifiyl-3,5-O-benzenylidene-L-xylitol (5) was constructed in six steps from protected D-xylose. Substitution of 5 with protected 8-bromoinosine 6 gave the key intermediate 5 ' -O-TBS-2 ' ,3 ' -di-O-acctyl-N-1-(2 ' -deoxy-1 ' ,4 ' -anhydro-3 ' ,5 ' -O-benzenylidene (14). Selective removal of 5 ' -O-TBS-group gave the corresponding though phosphorylation which was characterized by X-ray crystallographical analysis.
文摘Thiazine sugar derivative 2 was synthesized and characterized by IR, NMR and H RMS, and its crystal structure was determined by X-ray diffraction analysis. The crystal is of monoclinic system （C16H24N2O8S2, Mr = 436.49） with space group P21, a = 10.311（2）, b = 9.1198（18）, c = 11.623（2）A, β = 109.47（3）°, V= 1030.4（4）A^3, Z= 2, Dc = 1.407 g/cm^3, F（000）= 460, μ= 0.303 mm^-1, the final R = 0.0437 and wR = 0.0561 for 1954 observed reflections （I 〉 2σ（I））. Nine hydrogen bonds were found. The absolute configuration of this molecule was confirmed by comparison with the original material.
