Phytol derived from chlorophyll hydrolysis in plants is metabolized via phytenal.

Phytol is the isoprenoid alcohol bound in ester linkage to chlorophyll, the most abundant photosynthetic pigment in plants. During leaf senescence, large amounts of phytol are released by chlorophyll degradation. However, the pathway of phytol catabolism in plants is unknown.

Identification of novel potential PI3Kα inhibitors for cancer therapy.

Phosphatidylinositol 3-kinase alpha (PI3Kα) is among the most important PI3K isoforms and has been associated with multiple human cancers. Therefore, PI3Kα has garnered considerable attention as a viable target for anticancer drug discovery, and thus the identification and development of highly potent inhibitors of this isoform has become an important line of research. Here, structure-based virtual screening, bioassays, and molecular dynamics simulations were performed to discover novel potential PI3Kα inhibitors.

In silico structure prediction and inhibition mechanism studies of AtHDA14 as revealed by homology modeling, docking, molecular dynamics simulation.

Histone deacetylases (HDACs) play a significant role in the epigenetic mechanism by catalyzing deacetylation of lysine on histone in both animals and plants. HDACs involved in growth, development and response to stresses in plants. Arabidopsis thaliana histone deacetylase 14 (AtHDA14) is found to localize in the mitochondria and chloroplasts, and it involved in photosynthesis and melatonin biosynthesis.

Heat-induced unfolding of apo-CP43 studied by fluorescence spectroscopy and CD spectroscopy.

CP43 is a chlorophyll-binding protein, which acts as a conduit for the excitation energy transfer. The thermal stability of apo-CP43 was studied by intrinsic fluorescence, exogenous ANS fluorescence, and circular dichroism spectroscopy. Under heat treatment, the structure of apo-CP43 changed and existed transition state occurred between 56 and 62 °C by the intrinsic, exogenous ANS fluorescence and the analysis of hydrophobicity.

Genomic distribution and possible functional roles of putative G-quadruplex motifs in two subspecies of Oryza sativa.

G-quadruplex is a stable, four-stranded DNA or RNA structure formed from guanine-rich regions and implicated in telomere maintenance, replication, gene regulation at transcription level or translation level, etc. Based on bioinformatics methods, we analyzed different putative G-quadruplex motifs (PGQMs) patterns in various genomic regions of two subspecies (indica and japonica) of Oryza sativa and the whole genomes of other 8 species. In total, in the 10 species we discussed, the PGQMs densities in monocots were higher than dicots.

The structural and functional role of the three tryptophan residues in Pin1.

Pin1, the only known isomerase catalyzing phosphorylated pSer/pThr-Pro motifs in proteins, plays unique roles in human diseases notably cancers and Alzheimer's disease. Herein, site-directed mutagenesis was employed to construct the tryptophan mutants of Pin1, including W11L, W34L, and W73L. Spectral methodologies, activity measurement, and proteinase resistance analysis were used to investigate the structural and functional role of the tryptophan residues in Pin1.

Role of pH in structural changes for Pin1 protein: an insight from molecular dynamics study.

Pin1 protein is closely associated with the pathogenesis of cancers and Alzheimer's disease (AD). Previously, we have shown the acid-induced denaturation of Pin1 was determined by means of fluorescence emission, synchronous fluorescence etc., indicating an intermediate state around chromophores in Pin1 at about 4.

Soluble expression of Spinach psbC gene in Escherichia coli and in vitro reconstitution of CP43 coupled with chlorophyll a only.

CP43 is a chlorophyll a (Chl a) and β-carotene (β-Car) binding protein encoded by psbC gene. In this study, psbC gene isolated from Spinach was expressed in Escherichia coli in soluble state. After lysis of the cells, the apoproteins purified by nickel affinity chromatography were examined by SDS-PAGE and Western-blot.

Insight into the structural stability of wild type and mutants of the tobacco etch virus protease with molecular dynamics simulations.

The efficiency and high specificity of tobacco etch virus protease (TEVp) has made it widely used for cleavage of recombinant fusion proteins. However, TEVp suffers from a few intrinsic defects such as self-cleavage, poorly expressed in E. coli and less soluble.

Could Pin1 help us conquer essential hypertension at an earlier stage? A promising early-diagnostic biomarker and its therapeutic implications for the disease.

Essential hypertension is a major risk factor for cardiovascular morbidity and mortality, and the early-diagnosis is very important for the prevention of essential hypertension. Previously, we found that Pin1, the only known enzyme isomerizing pSer/pThr-Pro motifs in proteins, may gradually become inactive under conditions of stress such as intracellular acidification and fever. Interestingly, essential hypertension and the dysfunction of Pin1 often synchronously occur with the increasing age.

Aluminum(III) interferes with the structure and the activity of the peptidyl-prolyl cis-trans isomerase (Pin1): a new mechanism contributing to the pathogenesis of Alzheimer's disease and cancers?

The enzyme peptidyl-prolyl cis-trans isomerase (Pin1) may play an important role in preventing the development of Alzheimer's disease (AD). The structural and functional stability of Pin1 is extremely important. Previously, we have determined the stability of Pin1 under stressed conditions, such as thermal treatment and acidic-pH.

The acidic pH-induced structural changes in Pin1 as revealed by spectral methodologies.

Pin1 is closely associated with the pathogenesis of cancers and Alzheimer's disease (AD). Previously, we have shown the characteristics of the thermal denaturation of Pin1. Herein, the acid-induced denaturation of Pin1 was determined by means of fluorescence emission, synchronous fluorescence, far-UV CD, ANS fluorescence and RLS spectroscopies.

Apoptosis induced by genipin in human leukemia K562 cells: involvement of c-Jun N-terminal kinase in G₂/M arrest.

Aim: To investigate the effect of genipin on apoptosis in human leukemia K562 cells in vitro and elucidate the underlying mechanisms.

Methods: The effect of genipin on K562 cell viability was measured using trypan blue dye exclusion and cell counting. Morphological changes were detected using phase-contrast microscopy.

Spectroscopic studies on the irreversible heat-induced structural transition of Pin1.

Previously, the mechanism of the thermal unfolding of Pin1 (on-line measurements) was studied, revealing that Pin1 has a relatively high thermal stability. However, it is still questionable whether the unfolding of Pin1 is reversible. In the present work, intrinsic tryptophan fluorescence, ANS fluorescence, RLS, FTIR and CD spectroscopies are used to evaluate the reversibility of the thermal unfolding of Pin1.

Improving detection of differentially expressed gene sets by applying cluster enrichment analysis to Gene Ontology.

Background: Gene set analysis based on Gene Ontology (GO) can be a promising method for the analysis of differential expression patterns. However, current studies that focus on individual GO terms have limited analytical power, because the complex structure of GO introduces strong dependencies among the terms, and some genes that are annotated to a GO term cannot be found by statistically significant enrichment.

Results: We proposed a method for enriching clustered GO terms based on semantic similarity, namely cluster enrichment analysis based on GO (CeaGO), to extend the individual term analysis method.

Kunitz-type trypsin inhibitor with high stability from Spinacia oleracea L. seeds.

The trypsin inhibitor SOTI was isolated from Spinacia oleracea L. seeds through ammonium sulfate precipitation, Sepharose 4B-trypsin affinity chromatography, and Sephadex G-75 chromatography. This typical Kunitz inhibitor showed remarkable stability to heat, pH, and denaturant.

A trypsin inhibitor from Cassia obtusifolia seeds: isolation, characterization and activity against Pieris rapae.

A trypsin inhibitor was isolated from Cassia obtusifolia by ammonium sulfate precipitation, Sepharose 4B-trypsin affinity and Sephadex G-75 chromatography. The inhibitor consisted of a single polypeptide chain with a molecular mass of 19, 812.55 Da.

Studies on Light Harvesting Complexes of Photosystem II in a Chlorophyll-deficient Barley Mutant NYB.

As compared with wild type barley, the LHCII content of NYB barley mutant reduced markedly and its polypeptide components also changed: the contents of 24 kD, 27 kD and 30 kD polypeptides reduced and 26 kD polypeptide was missing. Northern blot analysis with specific cab gene probe showed that there was no difference in the LHCII mRNA level between the wild and mutant barley, indicating the decreased LHCII level in mutant barley was not due to a reduced transcription or accumulation of its mRNA. The rudimentary development state of thylakoids in NYB barley may be correlated with the loss of 26 kD polypeptide.

Purification and Characterization of the Antenna Protein CP29 from Spinach Photosystem II.

A Chla/b-binding protein, CP29, was purified from PS II core complex of spinach by DEAE-Toyopearl-650S anion-exchange chromatography, after treatment with the mild nonionic detergent beta-dodecyl maltoside and high concentration of LiClO(4). At room temperature, purified CP29 had a maximum absorption at 677 nm and a fluorescence maximum at 681 nm and doublet CD signals which indicated the presence of excitonic interactions between chlorophylls. The pigment content of the CP29 was 5 D7 Chla molecules and 2 D3 Chlb molecules per CP29 polypeptide, which was determined by spectroscopic method.

Purification and Characterization of the Core Antenna CP43 of Photosystem II.

The core antenna CP43 of photosystem II was purified from the PSII core complex of spinach by DEAE-Toyopearl-650S anion-exchange chromatography, using the mild nonionic detergent beta-dodecyl maltoside and high concentration of LiClO(4). At room temperature, the purified CP43 has a maximum absorption at 671 nm, a fluorescence maximum at 683 nm and doublet CD signals which indicated the presence of excitonic interactions between some chlorophylls. The pigment content of the CP43 was 20 - 21 Chl a per CP43 polypeptide as determined by a spectroscopic method.

Purification and Characterization of a DTT-sensitive Protease Associated with PS II Particles.

A DTT-sensitive protease was purified by hydrophobic chromatography on butyl-Toyopearl 650 M and anion-exchange chromatography on DEAE-Sephadex A-50 from the 1 M NaCl extract of PS II particles. The results of SDS-PAGE and gel-filtration chromatography on Superose 12 Have showed that it is a monomeric protease with a MW of 37 000. The protease generated polypeptides of 13.