Mutations of CYP51A protein (Cytochrome P450 14-α Sterol demethylase) play a central role in the azole resistance of Aspergillus fumigatus The available structural models of CYP51A protein ofA. fumigatus are built based on that of Homo sapiens and that of Mycobacterium tuberculosis, of which the amino acid homology is only 38% and 29% compared with CYP51A protein ofA. fumigatus, respectively. In the present study, we constructed a new 3D structural model ofA. fumigatus CYP51A protein based on a recently resolved crystal structure of the homologous protein in the fungus S. cerevisiae, which shares 50% amino acid homology with A. fumigatus CYP51A protein. Three azole molecules, itraconazole, voriconazole, and posaconazole, were docked to the wild-type and the mutant A. fumigatus CYP51A protein models, respectively, to illustrate the impact of cyp51A mutations to azole-resistance. We found the mutations that occurred at L98, M220, and Y431 positions would decrease the binding affinity of azoles to the CYP51A protein and therefore would reduce their inhibitory effects. Additionally, the mutations of L98 and G432 would reduce the stability of the protein, which might lead to conformational change of its binding pocket and eventually the resistance to azoles.

CARK1 preferentially interacts with and phosphorylates ABA receptors of subfamily III; the phosphorylation site RCAR11T78 plays a substantial role in the activation of the ABA response pathway.

Drought stress hinders plant growth and development, and abscisic acid (ABA) stimulates plants to respond to drought. Here, to increase plant tolerance to drought, we designed three synthetic promoters (Ap, Dp, ANDp) to determine transcription activity and drought stress resistance in plants resulting from combinations of (1) synthetic promoters and (2) the functional genes CARK1 (cytosolic ABA receptor kinase 1) and RCAR11 (regulatory components of ABA receptor 11). Transient expression of eGFP and the dual-luciferase assay demonstrated that the basal transcriptional activities of Ap and ANDp were present at low levels under normal conditions, while the synthetic promoters were apparently induced upon either treatment of exogenous ABA or co-transformation with effector DREB2A (dehydration-responsive element binding protein 2A). Analysis of the transgenic plants (Ap:CARK1, Dp:CARK1, ANDp:CARK1, and Dp:RCAR11-Ap:CARK1) showed that the synthetic promoters Ap, Dp, and ANDp increased the expression of exogenous genes in transgenic plants upon treatment of ABA or d-mannitol. ANDp:CARK1 and Dp:RCAR11-Ap:CARK1 transgenic plants were sensitive to ABA and d-mannitol during cotyledon greening and root growth. A drought tolerance assay revealed that ANDp:CARK1 and Dp:RCAR11-Ap:CARK1 exhibited a higher survival rate than others upon drought stress. These results indicate that the combinations ANDp:CARK1 and Dp:RCAR11-Ap:CARK1 can be used to generate drought stress resistance in plants.

C-reactive protein (CRP) is widely used as a biomarker of inflammation. It plays important roles in innate immunity response as a member of pattern recognition receptors, by binding oxidation-specific epitopes including some intermediates of lipid oxidative chain reaction. The inferred antioxidative ability of CRP was ever demonstrated by only few in vitro evidences, and needs to be clarified especially in vivo . Herein, we expressed human CRP in three representative non-animal organisms ( Escherichia coli , Saccharomyces cerevisiae , and tobacco) inherently lacking the milieu for CRP signalling, and found CRP did possess an intrinsic antioxidative ability. Heterologous CRP could confer increased oxidative resistance in its recombinant E . coli and yeast cells and transgenic tobaccos. We also revealed a positive correlation between the antioxidative effect of CRP and its solubility. Only soluble CRP could exhibit distinct antioxidative activity, while the CRP aggregates might be instead toxic (probably pro-oxidative) to cells. Moreover, fusion with hyper-acidic minipeptides could remarkably improve CRP solubility, and meanwhile guarantee or enhance CRP antioxidative ability. These results not only provide a new insight for understanding the etiology of CRP-involved inflammations and diseases, and also endorse a potential of CRP biotechnological applications in developing new pharmaceutical therapies and improving plant oxidative resistance.