Synthesis of novel biscrown ethers with rigid cis/trans ethylene bridge

Two novel biscrown ethers with rigid cis/trans ethylene linker were synthesized via Wittig reaction in high yield （about 80%）. Their pure cisltrans-isomers were obtained by column chromatography separation. And their structure/configuration was confirmed by ^1H NMR,^ 13C NMR, ESI mass spectrum, elemental analysis and UV-vis speca＇a.

Study on the thermal decomposition kinetics of cis/trans-[Cu(gly)_(2)]·H_(2)O

The thermal decomposition reactions of the complexes cis/trans-[Cu(gly)_(2)]·H_(2)Owere studied by TG-DSC methods.The results showed that they have similar decomposition process,which occur in two steps.The first step is the loss of water and the second step is the decomposition of anhydrous complexes.But for cis-[Cu(gly)_(2)]·H_(2)O,the tempoerature of losing water is higher than that of trans-isomer.Their reaction mechanisms of the two-step decomposition were also proposed.

PBOND:Web Server for the Prediction of Proline and Non-Proline cis/trans Isomerization

PBOND is a web server that predicts the conformation of the peptide bond between any two amino acids. PBOND classifies the peptide bonds into one out of four classes, namely cis imide （cis-Pro）, cis amide （cis-nonPro）, trans imide （trans-Pro） and trans amide （trans-nonPro）. Moreover, for every prediction a reliability index is computed. The underlying structure of the server consists of three stages： （1） feature extraction, （2） feature selection and （3） peptide bond classification. PBOND can handle both single sequences as well as multiple sequences for batch processing. The predictions can either be directly downloaded from the web site or returned via e-mail. The PBOND web server is freely available at http：//195.251.198.21/pbond.html.

Expression of Pinl and Ki67 in Cervical Cancer and Their Significance

In order to investigate the expression levels of Pinl mRNA and protein in cervical cancer and its association with Ki67 and their clinical significance, amplification of Pinl gene was examined by RT-PCR, and the expression of both Pinl and Ki67 protein was detected by immunohistochemistry in cervical cancer tissues. It was shown that the expression levels of Pinl were higher in cervical cancer than in normal cervical tissues （P〈0.05）. The expression of Pinl protein was increased progressively along with the disease process from normal cervix to CIN and to cervical cancer （P〈0.05）. No significant difference in the Pinl expression was found between disease stages （FIGO）, pathological grades or pelvic lymph node metastasis status （P〉0. 05）. The expression of Pin1 was significantly higher in adenocarcinoma than in squamous carcinoma of the uterine cervix （P〈0.05）. In cervical cancer, the overexpression of Pinl was positively correlated with that of Ki67 （P〈 0. 05）. These results suggested that the overexpression of Pinl was closely related with cancer cell proliferation or progression of cervical cancer and contributed to oncogenesis. Pinl may serve as a potential marker for cervical cancer diagnosis.

The immunophilin CYCLOPHILIN28 affects PSII-LHCII supercomplex assembly and accumulation in Arabidopsis thaliana

In plant chloroplasts,photosystem II(PSII)complexes,together with light-harvesting complex II(LHCII),form various PSII-LHCII supercomplexes(SCs).This process likely involves immunophilins,but the underlying regulatory mechanisms are unclear.Here,by comparing Arabidopsis thaliana mutants lacking the chloroplast lumen-localized immunophilin CYCLOPHILIN28(CYP28)to wildtype and transgenic complemented lines,we determined that CYP28 regulates the assembly and accumulation of PSII-LHCII SCs.Compared to the wild type,cyp28 plants showed accelerated leaf growth,earlier flowering time,and enhanced accumulation of high molecular weight PSII-LHCII SCs under normal light conditions.The lack of CYP28 also significantly affected the electron transport rate.Blue native-polyacrylamide gel electrophoresis analysis revealed more Lhcb6 and less Lhcb4 in M-LHCII-Lhcb4-Lhcb6 complexes in cyp28 versus wild-type plants.Peptidyl-prolyl cis/trans isomerase(PPIase)activity assays revealed that CYP28 exhibits weak PPIase activity and that its K113 and E187 residues are critical for this activity.Mutant analysis suggested that CYP28 may regulate PSIILHCII SC accumulation by altering the configuration of Lhcb6 via its PPIase activity.Furthermore,the Lhcb6-P139 residue is critical for PSII-LHCII SC assembly and accumulation.Therefore,our findings suggest that CYP28 likely regulates PSII-LHCII SC assembly and accumulation by altering the configuration of P139 of Lhcb6 via its PPIase activity.

FKBP23 in ER binds to BiP specifically

FKBP23 was found in mouse endoplasmic reticulum (ER) in 1998. It consists of an N-terminal peptidyl-prolyl cis-trans isomerase (PPlase) domain and a C-terminal domain with Ca2+ binding sites. The fusion protein of mouse FKBP23 and glutathione S-transferase (GST), GST-FKBP23, and the fusion protein of BiP, a member of heat shock protein 70 (Hsp 70) in ER, and GST, GST-BiP, were subcloned in E. coli, expressed and purified. The fusion proteins were restrictively digested by Factor Xa (FaXa) to obtain the free cloned proteins FKBP23 and BiP. With the assay of adsorption of free FKBP23 or BiP with GST-BiP or GST-FKBP23 attached to the Glutathione-Sepharose 4B, the adsorbed FKBP23 or BiP could be detected by Immunoblot. It means that FKBP23 binds to BiP. Furthermore, BiP in leukocyte ER-extract can be adsorbed with GST-FKBP23 attached to the glutathione-Sepharose 4B. It shows that FKBP23 binds to natural BiP in ER, too. These experiments show that a PPIase binds to a molecular chaperone of the Hsp70 family.

Structural Basis for Ubiquitin Recognition by a Novel Domain from Human Phospholipase A2 Activating Protein

Ubiquitin (Ub) is an essential modifier conserved in all eukaryotes from yeast to human. Phospholipase A2 activating protein (PLAA), a mammalian homolog of yeast DOA1/UFD3.