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1.
The role of invariant water molecules in the activity of plant cysteine protease is ubiquitous in nature. On analysing the 11 different Protein DataBank (PDB) structures of plant thiol proteases, the two invariant water molecules W1 and W2 (W220 and W222 in the template 1PPN structure) were observed to form H-bonds with the Ob atom of Asn 175. Extensive energy minimization and molecular dynamics simulation studies up to 2 ns on all the PDB and solvated structures clearly revealed the involvement of the H-bonding association of the two water molecules in fixing the orientation of the asparagine residue of the catalytic triad. From this study, it is suggested that H-bonding of the water molecule at the W1 invariant site better stabilizes the Asn residue at the active site of the catalytic triad.  相似文献   
2.
The δ-zein, a minor component of the maize prolamin, shows extensive immunological cross-reactivity with α- and β-zeins. The adsorption of an anti-δ-zein serum sequentially with cross-reacting antigens revealed that only about 18% of the reactivity of the antiserum was directed to epitopes unique to δ-zein. The localization of the various zein classes within the protein bodies of endosperm cells is important to understanding the synthesis, sequestering, and utilization of these storage proteins. Sections of 28 days after pollination (DAP) isolated protein bodies and 18 and 40 DAP whole endosperms were reacted sequentially with whole anti-δ-zein serum and gold-conjugated protein A. The results showed intense gold labeling in the core (inside the peripheral zone) and weak labeling in the periphery of the sections. This localization was not definitive in view of the above-mentioned cross-reactivities. To obtain an unequivocal localization, the whole antiserum was adsorbed with α-, β-, and γ-zeins and rendered monospecific for δ-zein. Immunostaining of protein body sections with monospecific antiserum showed that gold label was exclusively in the core region of the protein body and appeared to be in discrete lines and zones especially in 18 DAP protein bodies. The data from localizations using the monospecific antiserum indicated that δ-zein occurs throughout the core region of the protein body, probably interspersed with α- and β-zeins. The location of δ-zein is consistent with that predicted from its order of degradation during seed germination.  相似文献   
3.
The immunochemical data from studies with polyclonal antisera to -zein1, the 27 kD component of the maize prolamin, indicated that the region containing 8 tandem repeats of the sequence PPPVHL is an immunodominant site. In one case, the entire antibody repertoire of an antiserum recognized epitope(s) within this region. Three 17-mer oligopeptides corresponding to the predicted antigenic epitopes of -zein1 were synthesized and reacted with three different anti--zein1 sera in order to map antigenic sites in the intact protein. These antisera yielded positive reactions with a 17-mer peptide (peptide 37), which was not in a hydrophilic maximum but derived from the repeat region. The same antisera gave little or no reaction with other peptides (peptides 38 and 39), both of which were in a hydrophilic maximum. In addition, an antiserum to peptide 37 reacted strongly with both the homologous antigen and the intact -zein1. Peptide 37 also blocked the binding of antisera to -zein1 in competition assays. Subsequently, the shorter 6-mer (peptide 82) and 12-mer (peptide 80) versions of peptide 37 were synthesized, and both reacted with anti-peptide 37 serum and also with each of the three anti--zein1 sera. In these reactions and in competition assays, the reactivity and the blocking ability increased in proportion to the length of the peptide. Based on these data, it was concluded that the repeat region of -zein1 is the site of one or more continuous immunodominant epitopes. The data also suggest that the repeat region is exposed on the surface of the folded protein and probably occur as a mobile, random coil.  相似文献   
4.
Immunization of mice with a synthetic GM3-lactam-BSA (bovine serum albumin) conjugate (designed to emulate the corresponding natural GM3-lactone conjugate), followed by fusion of splenocytes with myeloma cells, gave rise to more than 300 monoclonal hybridomas producing antibodies to GM3-lactam-BSA, which did not react with Glc-BSA and BSA. Eight antibody clones were randomly chosen from the positive 300 hybridomas. The eight clones, all belonging to the IgG class, were unreactive against GM3-ganglioside, whereas two antibodies (P5-1 and P5-3, both IgG1, ) reacted with GM3-ganglioside lactone. Binding of these two antibodies to the GM3-lactam-BSA conjugate was inhibited by soluble glycosides of GM2-, GM3-, and GM4-lactam and by GM3- and GM4-lactam, respectively, but not by Gb3 or asialo-GM1 and GM2-saccharides. A third antibody (P3; IgG2b, ) was inhibited by GM2-, GM3-, and GM4-lactam, but did not recognize GM3-ganglioside lactone.  相似文献   
5.
Improper timing of artificial insemination with respect to ovulation is one of the major factors hampering the conception rate in buffalo. The present study was an attempt to relate physio-chemical changes in estrual mucus to subsequent pregnancy status in order to find their optimal values for determining the time for artificial insemination (AI). Serum estradiol, total protein and dry matter contents of estrual mucus were evaluated to predict the subsequent pregnancy in 36 buffalo during October 1988 to February 1989. Serum estradiol was determined by radioimmunoassay (RIA); spinnbarkeit, dry matter and total protein were determined by standard methods. Multivariate probit analyses were carried out to relate these variables to subsequent pregnancy status. Elasticity and protein concentration were significantly related to prediction probability of pregnancy status, and they predicted the pregnancy status 86% of the times correctly (P < 0.05). The probability of pregnant animals being correctly classified was 0.76, whereas the corresponding value for non-pregnant animals was 0.95. The present study demonstrated the possibility of using such a statistical model on mucus characteristics for determining proper AI time for better conception rates in Nili-Ravi water buffalo.  相似文献   
6.
Response of microbial populations to environmental disturbance   总被引:18,自引:0,他引:18  
Taxonomic and genetic diversities of microbial communities disturbed by chemical pollutants were lower than in undisturbed reference communities. The dominant populations within the disturbed communities had enhanced physiological tolerances and substrate utilization capabilities, indicating that generalized physiological versatility is an adaptive characteristic of populations that successfully compete within disturbed communities.  相似文献   
7.
Abstract Introducing the genetically engineered microorganism Pseudomonas cepacia AC1100 into soil microcosms resulted in elevated taxonomic diversity determined by phenotypic analyses of culturable isolates and genetic diversity determined by analysis of the heterogeneity of total microbial community DNA reannealing kinetics. The greatest impact occurred when P. cepacia AC1100 was introduced along with the herbicide 2,4,5-T, which P. cepacia AC1100 can degrade. The data suggests that both changes in the balance of populations and genetic recombination contributed to the increased diversity.  相似文献   
8.
Twenty species of Cladocera are reported from the Nile, where lacustrine species dominate, and from Jebel Marra and the Red Sea Hills, where chydorids dominate. The community found in the Red Sea Hills is more typically desertic than that of Jebel Marra, which appears closely related to the fauna of the West and Central African Sahel.  相似文献   
9.
An -tocopherol-binding protein has been isolated and purified from rabbit heart cytosol. The purified protein had an apparent molecular mass of 14,200, as derived from SDS-PAGE. The content of the protein in rabbit heart was around 11.8 g per g of tissue. The binding of -tocopherol to the purified protein was rapid, reversible, and saturable. Neither nor tocopherol could displace the bound -tocopherol from the protein, suggesting a high specificity for -tocopherol. -Tocopherol-binding protein did not bind oleate. Transfer of -tocopherol from liposomes to mitochodria was stimulated 8-fold in the presence of the binding protein, suggesting that this protein may be involved in the intracellular transport of -tocopherol in the heart.  相似文献   
10.
Biochemical effects of sub lethal doses LC10 and LC20 of cypermethrin were studied on some enzymes and macromolecule activities of adult beetles of Tribolium castaneum (Herbst.). Cypermethrin caused disturbances in levels of all biochemical components under study. The dose of 0.78 ppm caused abnormalities in α‐amylase and FAA by increasing their activities i.e., 45.45% and 21.97% significantly. The higher sub lethal dose of 2.62 ppm disturbed all the parameters (AcP, α‐amylase, soluble protein and FAA) except AkP, which was decreased by 93.06%. Moreover, sub lethal doses either increased or decreased the levels of all parameters non‐significantly except AkP and FAA which were effected significantly by 87.92% and 14.29% at lower and higher doses, respectively. In the present studies, cypermethrin significantly enhanced the activity of AkP in both susceptible and resistant strains of T. castaneum adult beetles while FAA contents were increased significantly in resistant strain only. The activity of α‐amylase was significantly lowered in susceptible strain only.  相似文献   
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