Bioinformatics analysis and prediction for structure and function of nitric oxide synthase and similar proteins from Plasmodium berghei

ObjectiveTo search and analyze nitric oxide synthase (NOS) and similar proteins from Plasmodium berghei(Pb).MethodsThe structure and function of nitric oxide synthase and similar proteins from Plasmodium berghei were analyzed and predicted by bioinformatics.ResultsPbNOS were not available, but nicotinamide adenine dinucleotide 2′–phosphate reduced tetrasodium (NADPH)–cytochrome p450 reductase(CPR) were gained. PbCPR was in the nucleus of Plasmodium berghei, while 134aa–229aa domain was localize in nucleolar organizer. The amino acids sequence of PbCPR had the closest genetic relationship with Plasmodium vivax showing a 73% homology. The tertiary structure of PbCPR displayed the forcep–shape with wings, but no wings existed in the tertiary structure of its' host, Mus musculus(Mm). 137aa–200aa, 201aa–218aa, 220aa–230aa, 232aa–248, 269aa–323aa, 478aa–501aa and 592aa–606aa domains of PbCPR showed no homology with MmCPRs', and all domains were exposed on the surface of the protein.ConclusionsNOS can't be found in Plasmodium berghei and other Plasmodium species. PbCPR may be a possible resistance site of antimalarial drug, and the targets of antimalarial drug and vaccine. It may be also one of the mechanisms of immune evasion. This study on Plasmodium berghei may be more suitable to Plasmodium vivax. And 137aa–200aa, 201aa–218aa, 220aa–230aa, 232aa–248, 269aa–323aa, 478aa–501aa and 592aa–606aa domains of PbCPR are more ideal targets of antimalarial drug and vaccine.

Cytochrome b5 Reductase 1 Triggers Serial Reactions that Lead to Iron Uptake in Plants

Rhizosphere acidification is essential for iron （Fe） uptake into plant roots. Plasma membrane （PM） H＊-ATPases play key roles in rhizosphere acidification. However, it is not fully understood how PM H＋-ATPase activity is regulated to enhance root Fe uptake under Fe-deficient conditions. Here, we present evidence that cytochrome b5 reductase 1 （CBR1） increases the levels of unsaturated fatty acids, which stimulate PM H＋-ATPase activity and thus lead to rhizosphere acidification. CBRl-overexpressing （CBRI-OX） Arabidopsis thaliana plants had higher levels of unsaturated fatty acids （18：2 and 18：3）, higher PM H＊-ATPase activity, and lower rhizosphere pH than wild-type plants. By contrast, cbrl loss-of-function mutant plants showed lower levels of unsaturated fatty acids and lower PM H＊-ATPase activity but higher rhizosphere pH. Reduced PM H＊-ATPase activity in cbrl could be restored in vitro by addition of unsatu- rated fatty acids. Transcript levels of CBR1, fatty acids desaturase 2 （FAD2）, and fatty acids desaturase 3 （FAD3） were increased under Fe-deficient conditions. We propose that CBR1 has a crucial role in increasing the levels of unsaturated fatty acids, which activate the PM H＊-ATPase and thus reduce rhizosphere pH. This reaction cascade ultimately promotes root Fe uptake.

4-Hydroxycinnamic acid attenuates neuronal cell death by inducing expression of plasma membrane redox enzymes and improving mitochondrial functions

Many approaches to neurodegenerative diseases that focus on amyloid-βclearance and gene therapy have not been successful.Some therapeutic applications focus on enhancing neuronal cell survival during the pathogenesis of neurodegenerative diseases,including mitochondrial dysfunction.Plasma membrane(PM)redox enzymes are crucial in maintaining cellular physiology and redox homeostasis in response to mitochondrial dysfunction.Neurohormetic phytochemicals are known to induce the expression of detoxifying enzymes under stress conditions.In this study,mechanisms of neuroprotective effects of 4-hydroxycinnamic acid(HCA)were examined by analyzing cell survival,levels of abnormal proteins,and mitochondrial functions in two different neuronal cells.HCA protected two neuronal cells exhibited high expression of PM redox enzymes and the consequent increase in the NAD^(+)/NADH ratio.Cells cultured with HCA showed delayed apoptosis and decreased oxidative/nitrative damage accompanied by decreased ROS production in the mitochondria.HCA increased the mitochondrial complexes I and II activities and ATP production.Also,HCA increased mitochondrial fusion and decreased mitochondrial fission.Overall,HCA maintains redox homeostasis and energy metabolism under oxidative/metabolic stress conditions.These findings suggest that HCA could be a promising therapeutic approach for neurodegenerative diseases.

Cadmium sulfide as bifunctional mimics of NADH oxidase and cytochrome c reductase takes effect at physiological pH

Recently,a study of mimic enzyme has received more attentions.However,the investigation on the oxidoreductase activity of electron mediators in the biological respiratory chain is still rare.Herein,we found that cadmium sulfide(CdS)nanorods can catalyze the formation of superoxide anions.Due to the role of the photo-generated holes and the nicotinamide adenine dinucleotide(NADH)oxidation promoted by superoxide anion(O_(2)^(•−)),the CdS exhibits NADH oxidase-like activity and can be coupled with dehydrogenase to realize the recycling of NADH.It is worth mentioning that the bio-electron acceptor,cytochrome c(Cyt c),as a chromogenic substrate,can accept electrons transferred from O_(2)^(•−),which demonstrates the Cyt c reductase-like activity of CdS under physiological pH conditions.For different substrates,O_(2)^(•−)induced from CdS show oxidizing capacity for NADH and reducing capacity for Cyt c,which provides a new perspective for the in-depth study of new nanozyme.

N,P,or S-doped carbon nanotubes as dual mimics of NADH oxidase and cytochrome c reductase

Most nanozyme research is limited to oxidase and peroxidase.Here,we reported the N,P,or S doped carbon nanotubes(CNTs)for enzyme mimics of nicotinamide adenine dinucleotide(NADH)oxidase and cytochrome c(Cyt c)reductase.Through the doping of N element,the NADH oxidase-like activity of CNTs is highly improved,the maximum initial velocity for N doped CNT(N-CNT)is increased by 4.28 times compared to that before the modification.Through the analysis of NADH oxidation products,we found that biologically active NAD+was produced,the oxygen was selectively reduced to water or hydrogen peroxide,which is consistent with natural NADH oxidase.Furthermore,we found for the first time that carbon nanotubes can promote the transfer of electrons from NADH to Cyt c,thereby can mimic the properties of Cyt c reductase.

Functional expression and regulation of eukaryotic cytochrome P450 enzymes in surrogate microbial cell factories

Cytochrome P450(CYP)enzymes play crucial roles during the evolution and diversification of ancestral monocel-lular eukaryotes into multicellular eukaryotic organisms due to their essential functionalities including catalysis of housekeeping biochemical reactions,synthesis of diverse metabolites,detoxification of xenobiotics,and con-tribution to environmental adaptation.Eukaryotic CYPs with versatile functionalities are undeniably regarded as promising biocatalysts with great potential for biotechnological,pharmaceutical and chemical industry applica-tions.Nevertheless,the modes of action and the challenges associated with these membrane-bound proteins have hampered the effective utilization of eukaryotic CYPs in a broader range.This review is focused on comprehen-sive and consolidated approaches to address the core challenges in heterologous expression of membrane-bound eukaryotic CYPs in different surrogate microbial cell factories,aiming to provide key insights for better studies and applications of diverse eukaryotic CYPs in the future.We also highlight the functional significance of the previously underrated cytochrome P450 reductases(CPRs)and provide a rational justification on the progression of CPR from auxiliary redox partner to function modulator in CYP catalysis.