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1.
Olive (Olea europaea L.) pollen is a major health concern in the Mediterranean countries and some olive growing regions in America and Australia. The molecular variability of pollen allergens constitutes a handicap for commercial extract standardization, which is the base of current diagnosis and vaccination procedures. In this paper, we report a time‐saving and plant material saving multiplex detection method for the rapid and simultaneous analysis of Ole e 1, Ole e 2, and Ole e 5 allergen polymorphism on a single blot. This method combines high‐resolution 2DE techniques with high‐sensitive fluorescence‐based detection methods. Using this strategy, we were capable to identify a higher number of allergen forms compared with classical 1D approach. The use of fluorescent probes and the increased resolution of 2D blots avoided overlapping effects, and allow estimating the amount of individual allergen forms. In addition, the pattern and identity of the IgE‐reactive proteins of either a population or individual patients allergic to olive pollen was also effortlessly determined in a single additional step. This flexible method might be extended to a higher number of olive allergens and cultivars, and is also applicable to other allergogenic plant species and sources.  相似文献   

2.
Standardization of pollen protein extracts is essential in order to ensure efficiency and safety in allergy diagnosis and immunotherapy. In this paper, we have optimized a multiplex Western blotting method for the simultaneous detection of four olive pollen allergens (Ole e 1, Ole e 2, Ole e 5, and Ole e 9) on a single blot using a monoclonal antibody from mouse and three polyclonal antibodies raised in rabbit. We utilized unconjugated Fab antibody fragments for blocking rabbit primary antibodies, and fluorescence-based detection. These changes allowed an accurate and reliable comparative quantitation of these allergens among pollen-protein samples from six olive cultivars. In addition, we also tested the IgE-binding capacity of these pollen extracts by reprobing the same blot with a pool of sera from eight patients allergic to olive and detection with enzyme conjugated antibodies. A noticeable variability regarding allergen content and IgE-reactivity was found among the olive cultivars analyzed. Moreover, we could easily confirm the identity of some of the IgE-binding proteins by simply overlapping both fluorescence and chemiluminescence images. This method is versatile since it can be applied to other allergogenic plant species and extended to other allergens.  相似文献   

3.
The severe acute respiratory syndrome coronavirus 2, also known as SARS-CoV-2, is the causative agent of the COVID-19 global pandemic. SARS-CoV-2 has a highly conserved non-structural protein 12 (NSP-12) involved in RNA-dependent RNA polymerase (RdRp) activity. For the identification of potential inhibitors for NSP-12, computational approaches such as the identification of homologous proteins that have been previously targeted by FDA-approved antivirals can be employed. Herein, homologous proteins of NSP-12 were retrieved from Protein DataBank (PDB) and the evolutionary conserved sequence and structure similarity of the active site of the RdRp domain of NSP-12 was characterized. The identified homologous structures of NSP-12 belonged to four viral families: Coronaviridae, Flaviviridae, Picornaviridae, and Caliciviridae, and shared evolutionary conserved relationships. The multiple sequences and structural alignment of homologous structures showed highly conserved amino acid residues that were located at the active site of the RdRp domain of NSP-12. The conserved active site of the RdRp domain of NSP-12 was evaluated for binding affinity with the FDA-approved antivirals, i.e., Sofosbuvir and Dasabuvir in a molecular docking study. The molecular docking of Sofosbuvir and Dasabuvir with the active site that contains conserved motifs (motif A-G) of the RdRp domain of NSP-12 revealed significant binding affinity. Furthermore, MD simulation also inferred the potency of Sofosbuvir and Dasabuvir. In conclusion, targeting the active site of the RdRp domain of NSP-12 with Dasabuvir and Sofosbuvir might reduce viral replication and pathogenicity and could be further studied for the treatment of SARS-CoV-2.  相似文献   

4.
Leishmaniosis, caused by intracellular parasites of the genus Leishmania, has become a serious public health problem around the world, and for which there are currently extensive limitations. In this work, a theoretical model was proposed for the development of a multi-epitope vaccine. The protein GP63 of the parasite was selected for epitopes prediction, due to its important biological role for the infection process and abundance. IEDB tools were used to determine epitopes B and T in Leishmania braziliensis; besides, other conserved epitopes in three species were selected. To improve immunogenicity, 50S ribosomal protein L7 / L12 (ID: P9WHE3) was used as a domain of adjuvant in the assembly process. The folding arrangement of the vaccine was obtained through homologous modeling multi-template with MODELLER v9.21, and a Ramachandran plot analysis was done. Furthermore, physicochemical properties were described with the ProtParam tool and secondary structure prediction combining GOR-IV and SOPMA tools. Finally, a molecular dynamics simulation (50 ns) was performed to establish flexibility and conformational changes. The analysis of the results indicates high conservancy in the epitopes predicted among the four species. Moreover, Ramachandran plot, physicochemical parameters, and secondary structure prediction suggest a stable conformation of the vaccine, after a minimum conformational change that was evaluated with the free energy landscape. The conformational change does not drive any substantial change for epitope exposition on the surface. The vaccine proposed could be tested experimentally to guide new approaches in the development of pan-vaccines; vaccines with regions conserved in multiple species.  相似文献   

5.
Intein-mediated protein splicing is a self-catalytic process in which the intervening intein sequence is removed from a precursor protein and the flanking extein segments are ligated with a native peptide bond. Splice junction proximal residues and internal residues within the intein direct these reactions. The identity of these residues varies in each intein, as groups of related residues populate conserved motifs. Although the basics of the four-step protein splicing pathway are known, mechanistic details are still unknown. Structural and kinetic analyses are beginning to shed some light. Several structures were reported for precursor proteins with mutations in catalytic residues, which stabilize the precursors for crystallographic study. Progress is being made despite limitations inherent in using mutated precursors. However, no uniform mechanism has emerged. Kinetic parameters were determined using conditional trans-splicing (splicing of split precursor fragments after intein reassembly). Several groups concluded that the rate of the initial acyl rearrangement step is rapid and Asn cyclization (step 3) is slow, suggesting that this latter step is rate limiting. Understanding the protein splicing pathway has allowed scientists to harness inteins for numerous applications.  相似文献   

6.
Standardization of protein extracts for clinical purposes represents an important task in order to maintain adequate reactivity, presence of the relevant allergens, and safety among other factors. The main objective of this work was to explore the potential use of a chip‐based automated CE system commercially available to analyze several of the most common forms of allergenic extracts from olive pollen used in allergy clinics. These include experimental extracts prepared from olive pollens, in‐house reference extracts, extracts designed for skin prick test assays, and a panel of vaccine variants aimed to specific immunotherapy. As a major conclusion of the study, chip‐based CE allowed in all cases to determine accurate protein profiles with different degrees of sensitivity, where several allergens (particularly the major olive pollen allergen Ole e 1) were easily recognized. Moreover, several purified allergens were also analyzed by this method, and proposed as specific standards for different purposes. In the present condition, the method can only provide the protein profile of the extracts with respect to a preestablished standard extract, but not allergen identification. However, these and other future developments and applications are discussed.  相似文献   

7.
This review is to summarize three new QSAR (quantitative structure-activity relationship) methods recently developed in our group and their applications for drug design. Based on more solid theoretical models and advanced mathematical techniques, the conventional QSAR technique has been recast in the following three aspects. (1) In the fragment-based two dimensional QSAR, or abbreviated as FB-QSAR, the molecular structures in a family of drug candidates are divided into several fragments according to the substitutes being investigated. The bioactivities of drug candidates are correlated with physicochemical properties of the molecular fragments through two sets of coefficients: one is for the physicochemical properties and the other for the molecular fragments. (2) In the multiple field three dimensional QSAR, or MF-3D-QSAR, more molecular potential fields are integrated into the comparative molecular field analysis (CoMFA) through two sets of coefficients: one is for the potential fields and the other for the Cartesian three dimensional grid points. (3) In the AABPP (amino acid-based peptide prediction), the bioactivities of peptides or proteins are correlated with the physicochemical properties of all or partial residues of the sequence through two sets of coefficients: one is for the physicochemical properties of amino acids and the other for the weight factors of the residues. Meanwhile, an iterative double least square (IDLS) technique is developed for solving the two sets of coefficients in a training dataset alternately and iteratively. Using the two sets of coefficients, one can predict the bioactivity of a query peptide, protein, or drug candidate. Compared with the old methods, the new QSAR approaches as summarized in this review possess machine learning ability, can remarkably enhance the prediction power, and provide more structural information. Meanwhile, the future challenge and possible development in this area have been briefly addressed as well.  相似文献   

8.
Internal repeats in protein sequences play a significant role in the evolution of protein structure and function. Applications of different bioinformatics tools help in the identification and characterization of these repeats. In the present study, we analyzed sequence repeats in a non-redundant set of proteins available in the Protein Data Bank (PDB). We used RADAR for detecting internal repeats in a protein, PDBeFOLD for assessing structural similarity, PDBsum for finding functional involvement and Pfam for domain assignment of the repeats in a protein. Through the analysis of sequence repeats, we found that identity of the sequence repeats falls in the range of 20–40% and, the superimposed structures of the most of the sequence repeats maintain similar overall folding. Analysis sequence repeats at the functional level reveals that most of the sequence repeats are involved in the function of the protein through functionally involved residues in the repeat regions. We also found that sequence repeats in single and two domain proteins often contained conserved sequence motifs for the function of the domain.  相似文献   

9.
An aspartic protease gene from Pleurotus ostreatus (Po-Asp) had been cloned based on the 3′ portion of cDNA in our previous work. The Po-Asp cDNA contained 1,324 nucleotides with an open reading frame (ORF) of 1,212 bp encoding 403 amino acid residues. The putative amino acid sequence included a signal peptide, an activation peptide, two most possible N-glycosylation sites and two conserved catalytic active site. The mature polypeptide with 327 amino acid residues had a calculated molecular mass of 35.3 kDa and a theoretical isoelectric point of 4.57. Basic Local Alignment Search Tool analysis showed 68–80 % amino acid sequence identical to other basidiomycetous aspartic proteases. Sequence comparison and evolutionary analysis revealed that Po-Asp is a member of fungal aspartic protease family. The DNA sequence of Po-Asp is 1,525 bp in length without untranslated region, consisting of seven exons and six introns. The Po-Asp cDNA without signal sequence was expressed in Pichia pastoris and sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated the molecular mass of recombinant Po-Asp was about 43 kDa. The crude recombinant aspartic protease had milk-clotting activity.  相似文献   

10.
More than ten β-glycosyltransferases are now recognized that have limited similarity to the amino acid sequence of cellulose synthase from Acetobacter xylinum. Using hydrophobic cluster analysis (HCA), we recently identified two domains and putative catalytic residues in the processive β-glycosyltransferases. In this study, we have found expressed sequence tags (ESTs) from higher plants (Arabidopsis thaliana, Brassica campestris, and Oryza sativa) that exhibit a limited sequence similarity to the A. xylinum cellulose synthase. These ESTs contain some of the conserved residues identified in the processive β-glycosyltransferases. Complete sequencing of an EST clone (T88271) from A. thaliana led to the identification of all the conserved residues in the derived truncated polypeptide which appears to be part of a putative cellulose synthase. Sequence comparison of proteins with known function and several unidentified proteins have the ‘D, D, D35Q(R,Q)XRW’ motif which is considered a strong predictor for β-glycosyltransferasesthat includes, among other proteins, cellulose and chitin synthases. The first two conserved aspartic acid residues in this motif were analysed by site-directed mutagenesis, and their replacement by another amino acid led to a loss of cellulose synthase activity in A. xylinum, suggesting that they are essential for enzyme activity. A correlation between the second residue (R or Q) in the Q(R,Q)XRW sequence and the synthesis of along glucan chain (polysaccharide) or a short glucan chain(oligosaccharide) suggests that this residue may be involved in the degree of processivity This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

11.
Reactivity-based selection strategies have been used to enrich combinatorial libraries for encoded biocatalysts having revised substrate specificity or altered catalytic activity. This approach can also assist in artificial evolution of enzyme catalysis from protein templates without bias for predefined catalytic sites. The prevalence of covalent intermediates in enzymatic mechanisms suggests the universal utility of the covalent complex as the basis for selection. Covalent selection by phosphonate ester exchange was applied to a phage display library of antibody variable fragments (scFv) to sample the scope and mechanism of chemical reactivity in a naive molecular library. Selected scFv segregated into structurally related covalent and noncovalent binders. Clones that reacted covalently utilized tyrosine residues exclusively as the nucleophile. Two motifs were identified by structural analysis, recruiting distinct Tyr residues of the light chain. Most clones employed Tyr32 in CDR-L1, whereas a unique clone (A.17) reacted at Tyr36 in FR-L2. Enhanced phosphonylation kinetics and modest amidase activity of A.17 suggested a primitive catalytic site. Covalent selection may thus provide access to protein molecules that approximate an early apparatus for covalent catalysis.  相似文献   

12.
The prevalence of allergic disorders has increased over the past few decades and the quality of life has been significantly influenced at least for the allergic subjects. Allergen avoidance is thought to be the best way of preventing clinical manifestation of the disease, however, it is not possible for some allergens, and other pharmacological and/or immunological treatment has to be made. Repetitive injection of sensitized allergens to the patients (immunotherapy) is the only known curative approach to the disease even though the exact mechanism is not clear to date. Crude extract of allergens has lots of shortcomings which might arouse unexpected results. Genetic engineering and recombinant allergens are thought to be one of the alternative ways to overcome these limitations. Genetic engineering could facilitate the investigation of immune responses of the subjects especially on B cell and T cell epitopes, and produce the therapeutic allergens which might minimize the possible side effects. Furthermore, conjugation of immuno-modulatory molecules such as CpG-ODN, cytokines, or toxins which could act specifically to the given allergens, and maleylation of the allergens could maximize the prophylactic or therapeutic effect. Immunotherapies for the pollen allergy and insect sting allergy have been thought to be successful. House dust mite allergy and cockroach allergy have been reported less beneficial by immunotherapeutic approaches. Cockroaches are one of the most important causes of asthma, and severe complications are often reported in the children in city dwellers with low-incomes. The studies of the biological functions of cockroach allergens and the use of recombinant allergens should allow understanding of mechanisms of cockroach-elicited allergic disorders and development of allergen-specific and sensitive diagnostics and tailored therapeutic approaches in the future.  相似文献   

13.
Sequences of dUTPases encoded by Alpha- and Gammaherpesviruses resemble other dUTPases in their possession of five conserved motifs, but differ in having greater chain lengths (about twice as long) and in the location of Motif 3 at an N terminal location relative to the other motifs. It was proposed that the herpesvirus gene arose by intragenic duplication of a standard dUTPase coding sequence and subsequent loss of one copy of each motif from the double length chain, and that the resulting enzyme was active as a monomer. With knowledge of the trimeric 3D structure of standard dUTPases, it is possible to suggest transformations that occurred in evolutionary development of the herpesvirus dUTPase. The distinct location of Motif 3 can indeed be seen to be consistent with it contributing to a single intramolecular active site with the other motifs. Separately, the occurrence in herpesvirus dUTPases of around 20 to 40 additional residues between Motifs 4 and 5 allows the C-terminal Motif 5 to reach the active site intramolecularly. The driving force behind these evolutionary changes remains obscure. We speculate that they may have allowed acquisition of a novel, presently unknown function by the protein. Consistent with this idea is the observation that in Alpha- and Gammaherpesvirus dUTPases the original locus of Motif 3 is occupied by a distinct conserved sequence (Motif 6); perhaps this element constitutes part of a separate functional capability. Notably, the apparently orthologous protein in Betaherpesviruses lacks the standard motifs while Motif 6 is still present.  相似文献   

14.
The reaction of [MoO(2)Cl(2)(di-tBu-bipy)] (1) (di-tBu-bipy = 4,4'-di-tert-butyl-2,2'-bipyridine) with water at 100-120 °C in a Teflon-lined stainless steel autoclave, in an open reflux system, or in a microwave synthesis system gave the octanuclear complex [Mo(8)O(22)(OH)(4)(di-tBu-bipy)(4)] (2) as a microcrystalline powder in good yields. Single crystals of 2 suitable for X-ray diffraction were obtained by the reaction of MoO(3) and di-tBu-bipy in water at 160 °C for 3 days. The molecular structure of 2 comprises a purely inorganic core, Mo(4)O(8)(μ(3)-OH)(2)(μ(2)-O)(2), attached to two peripheral oxo-bridged binuclear units, Mo(2)O(4)(μ(2)-O)(2)(OH)(di-tBu-bipy)(2). The inorganic core is composed of a unique assembly of four {MoO(5)} distorted square pyramids connected to each other via edge-sharing. Overall, the octanuclear complex adopts a highly distorted form strongly resembling an "S"-shaped molecular unit. Complex 2 was applied in the catalytic epoxidation of the biorenewable olefins DL-limonene (Lim) and methyl oleate (Ole), using tert-butylhydroperoxide (TBHP) as an oxygen donor, under mild reaction conditions (55 °C, air). The reactions of Lim and Ole gave the respective epoxide monomers in fairly high selectivities at high conversions (89% 1,2-epoxy-p-menth-8-ene selectivity at 96% Lim conversion; 99% methyl 9,10-epoxystearate selectivity at 94% Ole conversion, reached within 24 h reaction). Iodometric titrations revealed no measurable "non-productive" decomposition of TBHP.  相似文献   

15.
Abstract— Cloning and sequence analysis of cDNA for the luciferases of Pyrocoelia miyako and Hotaria parvula were carried out (GenBank accession numbers L39928 and L39929, respectively). The amino acid sequence, deduced from the nucleotide sequence, showed P. miyako luciferase to consist of 548 amino acid residues with a molecular weight of 60955, while the luciferase of H. parvula consisted of 548 amino acid residues with a molecular weight of 60 364. Pyrocoelia miyako luciferase showed 82.1 % homology with the luciferase of Photinus pyralis and less than 70% homology with other firefly luciferases, whereas H. parvula luciferase showed 98%, 82.5% and 81.2% homology with the luciferases of Luciola mingrelica, Luciola lateralis and Luciola cruciata, respectively. Two regions in the enzymes were found to be highly conserved. The amino acid sequences were used to construct a phylogenetic tree, which showed that the fireflies could be divided into two groups.  相似文献   

16.
Heme oxygenase (HO, EC 1.14.99.3) catalyzes the oxidation of heme and performs vital roles in plant development and stress responses. Two HO isozymes exist in plants. Between these, HO-1 is an oxidative stress-response protein, and HO-2 usually exhibited constitutive expression. Although alfalfa HO-1 gene (MsHO1) has been investigated previously, HO2 is still poorly understood. In this study, we report the cloning and characterization of HO2 gene, MsHO2, from alfalfa (Medica sativa L.). The full-length cDNA of MsHO2 contains an ORF of 870 bp and encodes for 290 amino acid residues with a predicted molecular mass of 33.3 kDa. Similar to MsHO1, MsHO2 also appears to have an N-terminal transit peptide sequence for chloroplast import. Many conserved residues in plant HO were also conserved in MsHO2. However, unlike HO-1, the conserved histidine (His) required for heme-iron binding and HO activity was replaced by tyrosine (Tyr) in MsHO2. Further biochemical activity analysis of purified mature MsHO2 showed no HO activity, suggesting that MsHO2 may not be a true HO in nature. Semi-quantitative RT-PCR confirmed its maximum expression in the germinating seeds. Importantly, the expression levels of MsHO2 were up-regulated under sodium nitroprusside (SNP) and H(2)O(2) (especially) treatment, respectively.  相似文献   

17.
In this paper, we report (a) the development of ZnO thin films prepared by pulsed laser deposition and partially covered with nano-particles Pd or Au and (b) their physicochemical study, in order to investigate their catalytic and/or adsorptive properties. It is the first time where two different and popular methods, namely pulsed laser deposition and reversed flow-inverse gas chromatography, are combined. The inverse gas chromatographic technique with the corresponding time-resolved analysis is used for the first time in order to characterise compounds in the nano-scale domain. We focus on the determination of physicochemical quantities mainly concerning the adsorption in thin films, with (Pd/ZnO) or without (Au/ZnO) catalytic behaviour. Thus, entropy and other important physicochemical quantities are calculated which reveal the mechanism of adsorption as well as of isomerization-hydrogenation of 1-butene and contribute to the study of heterogeneity of thin film surfaces. The programs used have been written in Fortran. An important achievement is also the determination of the standard deviations of the kinetic constants.  相似文献   

18.
Polyphenol oxidases (PPOs) are widely distributed enzymes among animals, plants, bacteria, and fungi. PPOs often have significant role in many biologically essential functions including pigmentation, sclerotization, primary immune response, and host defense mechanisms. In the present study, forty-seven full-length amino acid sequences of PPO from bacteria, fungi, and plants were collected and subjected to multiple sequence alignment (MSA), domain identification, and phylogenetic tree construction. MSA revealed that six histidine, two phenylalanine, two arginine, and two aspartic acid residues were highly conserved in all the analyzed species, while a single cysteine residue was conserved in all the plant and fungal PPOs. Two major sequence clusters were constructed by phylogenetic analysis. One cluster was of the plant origin, whereas the other one was of the fungal and bacterial origin. Motif GGGMMGDVPTANDPIFWLHHCNVDRLWAVWQ was found in all the species of bacterial and fungus sources. In addition, seven new motifs which were unique for their group were also identified.  相似文献   

19.
The primary structure of saporin-S9 and MAP-S, two type-1 ribosome-inactivating proteins isolated from the seeds of Saponaria officinalis L. and Mirabilis jalapa, respectively, was determined using a combined approach based on Edman degradation and electrospray ionization mass spectrometry (ESMS). Saporin-S9 has 253 amino acids with a calculated molecular mass of 28,492.99, which is in good agreement with that determined by ESMS (28 495 +/- 2 Da). Unlike other saporins with known primary structure, saporin-S9 contains four histidinyl residues (positions 111, 121, 216 and 248). By comparing the amino acid sequence of saporin-S9 with that of saporin-S6, we found 22 amino acid substitutions (8.7%), 13 of which are conservative and nine non-conservative. The residues known to be involved in the definition of the active site and with RNA base recognition are conserved. The four histidinyl residues and especially Lys for Gln203 contribute to the higher calculated pI value (10.17) of saporin-S9 compared with saporin-S6 (9.98). MAP-S contains 250 amino acid residues with a calculated molecular mass of 27,789.49, in good agreement with that determined by ESMS (27,789 +/- 2). Cys36 and Cys220 form a disulphide bridge and only four amino acid residues are different from the amino acid sequence of MAP, isolated from the roots of the same plant, i.e. Leu34 (Glu), Ile161 (Leu), Asp185 (Glu) and Asp191 (Glu) (in parentheses, the residues present in MAP). The reported approach can provide rapid and reliable sequence screening in the analysis of homologous proteins, including the presence of disulphide bridges.  相似文献   

20.
The objective of the study was to check the authenticity of Hungarian honey using physicochemical analysis, near infrared spectroscopy, and melissopalynology. In the study, 87 samples from different botanical origins such as acacia, bastard indigo, rape, sunflower, linden, honeydew, milkweed, and sweet chestnut were collected. The samples were analyzed by physicochemical methods (pH, electrical conductivity, and moisture), melissopalynology (300 pollen grains counted), and near infrared spectroscopy (NIRS:740–1700 nm). During the evaluation of the data PCA-LDA models were built for the classification of different botanical and geographical origins, using the methods separately, and in combination (low-level data fusion). PC number optimization and external validation were applied for all the models. Botanical origin classification models were >90% and >55% accurate in the case of the pollen and NIR methods. Improved results were obtained with the combination of the physicochemical, melissopalynology, and NIRS techniques, which provided >99% and >81% accuracy for botanical and geographical origin classification models, respectively. The combination of these methods could be a promising tool for origin identification of honey.  相似文献   

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