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1.
Glycomics-driven discoveries in schistosome research 总被引:2,自引:0,他引:2
Schistosome glycans and glycoconjugates play a prominent role in the parasite's biology, in particular in the interaction with the human host. A large amount of structural data regarding glycosylation of different schistosome life stages and glycoconjugate subsets has been collected in the last decade, but many significant gaps in our knowledge of the schistosomal glycome remain. Here we will present a concise review of the already available data guided by a selection of recently generated stage-specific glycan profiles, and discuss implications and prospects of glycomics studies of schistosomes. 相似文献
2.
Ki-Woong Han Jinsang Yoo Eun-Joo Oh Jeong Jin Choi Hyun-Kyu Kim Suk-Tae Kwon 《Biotechnology letters》2001,23(5):379-384
The gene (bglT) encoding Thermus caldophilus GK24 -glycosidase (Tca -glycosidase) was cloned and sequenced. The gene contains an open reading frame encoding 431 amino acids with a M
r of 48 658 Da. The bglT gene was expressed under the control of tac promoter on a high-copy plasmid in E. coli. The recombinant Tca -glycosidase was purified 41.5-fold with a 59% yield and a specific activity of 83 U mg–1 protein. 相似文献
3.
Nox1 is a membrane-integrated protein that belongs to the Nox family of superoxide-producing NADPH oxidases. Here we show that human Nox1 undergoes glycosylation at Asn-162 and Asn-236 in the second and third extracellular loops, respectively. Simultaneous threonine substitution for these residues completely abrogates the glycosylation, but does not prevent Nox1 from forming a heterodimer with p22phox, trafficking to the cell surface, or producing superoxide. In the absence of p22phox, Nox1 is transported to the plasma membrane mainly as a form with high mannose N-glycans, although their conversion into complex N-glycans is induced by expression of p22phox. These findings indicate that glycosylation and subsequent N-glycan maturation of Nox1 are both dispensable for its cell surface recruitment. Superoxide production by unglycosylated Nox1 is largely dependent on p22phox, which is abrogated by glutamine substitution for Pro-156 in p22phox, a mutation leading to a defective interaction with the Nox1-activating protein Noxo1. Thus p22phox directly contributes to Nox1 activation in a glycosylation-independent manner, besides its significant role in Nox1 glycan maturation. 相似文献
4.
Ribosome inactivating proteins and apoptosis 总被引:10,自引:0,他引:10
Ribosome inactivating proteins (RIPs) are protein toxins that are of plant or microbial origin that inhibit protein synthesis by inactivating ribosomes. Recent studies suggest that RIPs are also capable of inducing cell death by apoptosis. Though many reports are available on cell death induced by RIPs, the mechanism involved is not well studied. Comparison of pathways of apoptosis and cellular events induced by various RIPs suggests a central role played by mitochondria, probably acting as an integrator of cellular stress and cell death. The purpose of this review is to compare the various apoptotic pathways that may be involved and propose a general pathway in RIP-induced cell death. 相似文献
5.
Aaron J. Oakley 《Biochemical and biophysical research communications》2010,397(4):745-224
Phytases hydrolyse the phosphomonoesters of phytate (myo-inositol-1,2,3,4,5,6-hexakis phosphate) and thus find uses in plant and animal production through the mobilisation of phosphorus from this source. The structure of partially deglycosylated Aspergillus niger PhyA is presented in apo form and in complex with the potent inhibitor myo-inositol-1,2,3,4,5,6-hexakis sulfate, which by analogy with phytate provides a snapshot of the Michaelis complex. The structure explains the enzyme’s preference for the 3′-phosphate of phytate. The apo-and inhibitor-bound forms are similar and no induced-fit mechanism operates. Furthermore the enzyme structure is apparently unaffected by the presence of glycosides on the surface. The new structures of A. niger PhyA are discussed in the context of protein engineering studies aimed at modulating pH preference and stability. 相似文献
6.
The conformational dynamics of β-glycosidase from Sulfolobus solfataricus was investigated by following the emission decay arising from the large number of tryptophanyl residues that are homogeneously dispersed in the primary structure. The fluorescence emission is characterized by a bimodal lifetime distribution, suggesting that the enzyme structure contains rigid and flexible regions, properly located in the macromolecule. The enzyme activity and thermostability appear to be related to the dynamic properties of these regions as evidenced by perturbation studies of the enzyme structure at alkaline pH and by addition of detergents such as SDS. The pH increase affects the protein dynamics with a remarkable loss of thermal stability and activity; these changes occur without any significant variation in the secondary structure as revealed by far-UV dichroic measurements. In the presence of 0.02% (w/v) SDS at alkaline pH, the enzymatic activity and thermostability are recovered. Under these conditions, the conformational dynamics appear to be similar to that evidenced at neutral pH. Further increases in SDS concentration, at alkaline pH, render the activity and thermostability of β-glycosidase similar to those observed in the absence of detergent. Proteins 27:71–79 © 1997 Wiley-Liss, Inc. 相似文献
7.
Toshiya Kondo Takafumi Yoshikawa Yukio Ogihara Hajime Mizukami 《Biotechnology letters》2002,24(13):1117-1124
A genomic clone encoding mature karasurin-A (KRNA), a ribosome-inactivating protein from Trichosanthes kirilowii var. japonica, was efficiently expressed in E. coli using an expression cassette vector pMAL-c2. The resultant recombinant KRNA fused with maltose-binding protein (MBP) was recovered from the soluble fraction of the bacterial cells and purified to near homogeneity after one round of the affinity chromatography. Neither the karasurin precursor retaining both N- and C-terminal peptides, nor the protein with the N-terminal peptide was successufully produced even as a MBP-fusion. The protein with its C-terminal peptide was over-produced but was recovered in an insoluble fraction. Both the recombinant MBP-KRNA fusion protein and recombinant KRNA with MBP removed were as active as the native KRNA from root tubers. The immunogenicity of the recombinant KRNA was also unaffected by fusion with MBP. 相似文献
8.
Steviol is a diterpene isolated from the plant Stevia rebaudiana that has a potential role as an antihyperglycemic agent by stimulating insulin secretion from pancreatic beta cells and also has significant potential to diminish the renal clearance of anionic drugs and their metabolites. In this study, the lacS gene, which encodes a thermostable β-glycosidase (SSbgly) enzyme from the extremely thermoacidophillic archaeon Sulfolobus solfataricus, was cloned and expressed in E. coli Rossetta BL21(DE3)pLyS using lactose as an inducer. Through fermentation, SSbgly was expressed as a 61 kDa protein with activity of 24.3 U/mg and the OD600 of 23 was reached after 18 h induction with 10 mM lactose. Purified protein was obtained by Ni-Sepharose chromatography with a yield of 92.3%. SSbgly hydrolyzed steviol glycosides to produce steviol with a yield of 99.2%. The optimum conditions for steviol production were 50 U/ml SSbgly and 90 mg/ml Ste at 75 °C as determined by the response surface method. 相似文献
9.
Suleyman Akocak Parham Taslimi Nebih Lolak Mesut Işık Mustafa Durgun Yakup Budak Cüneyt Türkeş İlhami Gülçin Şükrü Beydemir 《化学与生物多样性》2021,18(4):e2000958
A series of six N-carbamimidoyl-4-(3-substituted phenylureido)benzenesulfonamide derivatives were synthesized by reaction of sulfaguanidine with aromatic isocyanates. In vitro and in silico inhibitory effects of the novel ureido-substituted sulfaguanidine derivatives were investigated by spectrophotometric methods for α-glycosidase (α-GLY), acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) enzymes associated with diabetes mellitus (DM) and Alzheimer's disease (AD). N-Carbamimidoyl-4-{[(3,4-dichlorophenyl)carbamoyl]amino}benzene-1-sulfonamide ( 2f ) showed AChE and BChE inhibitory effects, with KI values of 515.98±45.03 nM and 598.47±59.18 nM, respectively, while N-carbamimidoyl-4-{[(3-chlorophenyl)carbamoyl]amino}benzene-1-sulfonamide ( 2e ) showed strong α-GLY inhibitory effect, with KI values of 103.94±13.06 nM. The antidiabetic effects of the novel synthesized compounds are higher than their anti-Alzheimer's effects, because the inhibition effect of the compounds on the α-GLY with diabetic enzyme is greater than the effect on esterase enzymes. Indeed, inhibition of the metabolic enzymes is important for the treatment of DM and AD. 相似文献
10.
Scott CL Hartweck LM de Jesús Pérez J Chen D García JA Olszewski NE 《FEBS letters》2006,580(25):5829-5835
The capsid protein of Plum pox virus (PPV-CP) is modified with O-linked GlcNAc (O-GlcNAc). While Arabidopsis has two O-GlcNAc transferases, SECRET AGENT (SEC) and SPINDLY (SPY), previous work suggests that SEC modifies PPV-CP and that the modification plays a role in the infection process. Here, we show that when co-expressed in Escherichia coli SEC modifies PPV-CP. Deletion mapping and site-directed mutagenesis identified three threonine and a serine located near the N-terminus of PPV-CP that are modified by SEC. Two of these threonines have recently been shown to be modified in virus from plants suggesting that SEC has the same specificity in plants and E. coli. 相似文献