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1.
Eighteen consecutive uniform overlapping synthetic peptides that spanned the entire extracellular part (residues 1–210) of the α-chain ofTorpedo californica acetylcholine receptor were screened for binding activity of125I-labeled cobratoxin. Five toxin-binding regions were localized within residues 1–10, 32–41, 100–115, 122–150, and 182–198. The five toxin-binding regions may be distinct sites or, alternatively, different faces in one or more sites. 相似文献
2.
HepatitisBvirus(HBV),themajorcausativeagentofchronicviralhepatitisandlivercirrhosis,isstronglyconnectedwiththedevelopmentofhepatocellularcarcinoma.OneofthemostremarkablefeaturesofHBVinfectionisthatinfectedcellsproducemultipletypesofvirusrelatedparticle… 相似文献
3.
To clarify the ecological significance of the association of sulfate-reducing bacteria (SRB) with sediment particle size,
SRB utilizing lactate (l-SRB), propionate (p-SRB) and acetate (a-SRB) were examined with different sizes of sediment particles in a hypertrophic freshwater lake using the anaerobic plate
count method. The numbers ofl-SRB anda-SRB were 104–105 colony forming units (CFU) per ml in the 0–3 cm layer and 102–103 CFU ml−1 in the 10–13 cm layer while the numbers ofp-SRB were one or two orders lower than those ofl-SRB anda-SRB. A sediment suspension was fractionated into four fractions (<1, 1–10, 10–94 and >94 μm). The highest proportions ofl-SRB anda-SRB were found in the 10–94 μm fraction: 66–97% forl-SRB and 53–98% fora-SRB. The highest proportion ofp-SRB was found in the >94 μm fraction (70–74%). These results indicate that most SRB were associated with sediment particles.
One isolate from an acetate-utilizing enrichment culture was similar toDesulfotomaculum acetoxidans, a spore-forming sulfate-reducing bacterium. When lactate and sulfate were added to sediment samples,l-SRB anda-SRB in the <10 μm-fraction grew more rapidly than those in whole sediment for the first 2 days. This result suggests that
nutrients uptake by free-living and small particle-associated (<10 μm) SRB is higher than that by SRB associated with larger
particles. 相似文献
4.
Aftab A. Ansari 《Journal of biosciences》1985,7(3-4):315-322
Using hydrophilicity and recognition values of amino acids, the antigenic sites of theΒ-subunits of human choriogonadotropin and luteinizing hormone were computed from their amino acid sequences. Six antigenic
sites were calculated for human choriogonadotropinΒ-subunits: residues 3–8, 17–22, 59–65,100–106,110–116 and 134–139. For luteinizing hormoneΒ-chain three antigenic sites were calculated: residues 17–22,59–65, and 100–106; all these three sites of luteinizing hormoneΒ being identical to the corresponding sites in human choriogonadotropinΒ. There was no antigenic site in luteinizing hormone that was also not found in human choriogonadotropin. On the other hand,
there were unique determinants in human choriogonadotropin that were not found in luteinizing hormone; these determinants
were residues 3–8, 110–116 and 134–139 相似文献
5.
Han-liang Cheng Si-ping Sun Yong-xing Peng Xiao-yun Shi Xin Shen Xue-ping Meng Zhi-guo Dong 《Molecular biology reports》2010,37(6):2665-2673
A full-length cDNA coding lipoprotein lipase (LPL) was cloned from liver of adult common carp (Cyprinus carpio Var. Jian) by RT-PCR and rapid amplification of cDNA ends (RACE) approaches. The cDNA obtained was 2,411 bp long with a 1,524 bp
open reading frame (ORF) encoding 507 amino acids. This amino acid sequence contains two structural regions: N-terminus (24–354
residues) and C-terminus (355–507 residues). Before N-terminus, 1–23 residues is signal peptide, 6–23 residues is transmembrance
helix. At N-terminus, some conversed functional sites were found, including two N-linked glycosylation sites Asn41 and Asn88; one catalytic triad Ser174, Asp198 and His283; one conserved heparin-binding site Arg321 to Arg324 (RKNR); eight cysteines residues Cys69 and Cys82, Cys258 and Cys281, Cys306 and Cys325, Cys317 and Cys320 which are involved in four disulfide bridges; one polypeptide “lid” that participates in substrate specificity. At C-terminus,
Asn401 is another N-linked glycosylation site, and Trp434 and Trp435 (WW) is lipid-binding site. The amino acid sequence has a high similarity, and shows similar structural features to LPL of
other species. Tissue distribution of LPL mRNA in liver, head kidney, mesenteric adipose tissue, heart and white muscle of common carp was analyzed by semi-quantitative
RT-PCR method using β-actin gene as internal control. The result showed that the expressions of LPL mRNA were detected in all examined tissues of common carp. The expression levels of LPL in the mesenteric adipose tissue was highest among these tissues, following in liver and head kidney, and the lowest expression
was found in heart and white muscle. 相似文献
6.
Barbara Biondi Dante Goldin Elisa Giannini Roberta Lattanzi Lucia Negri Pietro Melchiorri Luigi Ciocca Raniero Rocchi 《International journal of peptide research and therapeutics》2006,12(2):139-144
Syntheses are described of the nociceptin (1–13) amide [NC(1–13)-NH2] and of several analogues in which either one or both the phenylalanine residues (positions 1 and 4), the arginine residues (positions 8 and 12) and the alanine residues (positions 7 and 11) have been replaced by N-benzyl-glycine, N-(3-guanidino-propyl)-glycine and β-alanine, respectively. The preparation is also described of NC(1–13)-NH2 analogues in which either galactose or N-acetyl-galactosamine are β-O-glycosidically linked to Thr5 and/or to Ser10. Preliminary pharmacological experiments on mouse vas deferens preparations showed that Phe4, Thr5, Ala7 and Arg8 are crucial residues for OP4 receptor activation. Manipulation of Phe1 yielded peptides endowed with antagonist activity but [Nphe1] NC(1–13)-NH2 acted as an antagonist still possessing weak agonist activity. Introduction of the βAla residue either in position 7 or 11 of the [Nphe1] NC(1–13)-NH2 sequence, abolished any residual agonist activity and [Nphe1, βAla7] NC(1–13)-NH2 and [Nphe1, βAla11] NC(1–13)-NH2 acted as competitive antagonists only. Modification of both Ala7 and Ala11 abolished the antagonist activity of [Nphe1]NC(1–13)-NH2 probably by hindering receptor binding. Changes at positions 10 and 11 gave analogues still possessing agonist activity. [Ser(βGal)10] NC(1–13)-NH2 displayed an activity comparable with that of NC(1–13)-NH2, [Ser(βGalNAc)10] NC(1–13)-NH2 and [βAla11] NC(1–13)-NH2 were five and 10 times less active, respectively.The α-amino acid residues are of the l-configuration. Standard abbreviations for amino acid derivatives and peptides are according to the suggestions of the IUPAC-IUB Commission on Biochemical Nomeclature (1984), Eur. J. Biochem. 138, 9–37. Abbreviations listed in the guide published in (2003), J. Peptide Sci. 9, 1–8 are used without explanation. 相似文献
7.
Passos FV Fleming HP Hassan HM McFeeters RF 《Applied microbiology and biotechnology》2003,63(2):207-211
The fermentation kinetics of Lactobacillus plantarum were studied in a specially designed broth formulated from commercially available, dehydrated components (yeast extract, trypticase, ammonium sulfate) in batch and continuous culture. During batch growth in the absence of malic acid, the specific growth rate was 0.20 h–1. Malic acid in the medium, at 2 mM or 10 mM, increased the specific growth rate of L. plantarum to 0.34 h–1. An increase in the maximum cell yield due to malic acid also was observed. Malic acid in the medium (12 mM) reduced the non-growth-associated (maintenance energy) coefficient and increased the biomass yield in continuous culture, based on calculations from the Luedeking and Piret model. The biomass yield coefficient was estimated as 27.4 mg or 34.3 mg cells mmol–1 hexose in the absence or presence of malic acid, respectively. The maintenance coefficient was estimated as 3.5 mmol or 1.5 mmol hexose mg–1 cell h–1 in the absence or presence of malic acid. These results clearly demonstrate the energy-sparing effect of malic acid on the growth- and non-growth-associated energy requirements for L. plantarum. The quantitative energy-sparing effect of malic acid on L. plantarum has heretofore not been reported, to our knowledge. 相似文献
8.
Jarvet J Danielsson J Damberg P Oleszczuk M Gräslund A 《Journal of biomolecular NMR》2007,39(1):63-72
NMR spectroscopy combined with paramagnetic relaxation agents was used to study the positioning of the 40-residue Alzheimer
Amyloid β-peptide Aβ(1–40) in SDS micelles. 5-Doxyl stearic acid incorporated into the micelle or Mn2+ ions in the aqueous solvent were used to determine the position of the peptide relative to the micelle geometry. In SDS solvent,
the two α-helices induced in Aβ(1–40), comprising residues 15–24, and 29–35, respectively, are surrounded by flexible unstructured
regions. NMR signals from these unstructured regions are strongly attenuated in the presence of Mn2+ showing that these regions are positioned mostly outside the micelle. The central helix (residues 15–24) is significantly
affected by 5-doxyl stearic acid however somewhat less for residues 16, 20, 22 and 23. This α-helix therefore resides in the
SDS headgroup region with the face with residues 16, 20, 22 and 23 directed away from the hydrophobic interior of the micelle.
The C-terminal helix is protected both from 5-doxyl stearic acid and Mn2+, and should be buried in the hydrophobic interior of the micelle. The SDS micelles were characterized by diffusion and 15N-relaxation measurements. Comparison of experimentally determined translational diffusion coefficients for SDS and Aβ(1–40)
show that the size of SDS micelle is not significantly changed by interaction with Aβ(1–40).
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
9.
Acid, alkaline and enzymatic hydrolysis of agricultural crop wastes were compared for yields of total reducing sugars with
the hydrolysates being evaluated for ethanol production using a mixed culture of Zymomonas mobilis and Candida tropicalis. Acid hydrolysis of fruit and vegetable residues gave 49–84 g reducing sugars l−1 and 29–32 g ethanol l−1 was then obtained. Alkaline hydrolysis did not give significant amount of reducing sugars. Enzymatic hydrolysis of fruit
and vegetable residues yielded 36–123 g reducing sugars l−1 and 11–54 g ethanol l−1. 相似文献
10.
Profile of the alpha-bungarotoxin-binding regions on the extracellular part of the alpha-chain of Torpedo californica acetylcholine receptor. 总被引:3,自引:0,他引:3
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The continuous alpha-neurotoxin-binding regions on the extracellular part (residues 1-210) of the alpha-chain of Torpedo californica acetylcholine receptor were localized by reaction of 125I-labelled alpha-bungarotoxin with synthetic overlapping peptides spanning this entire part of the chain. The specificity of the binding was confirmed by inhibition with unlabelled toxin and, for appropriate peptides, with unlabelled anti-(acetylcholine receptor) antibodies. Five toxin-binding regions were localized within residues 1-10, 32-41, 100-115, 122-150 and 182-198. The third, fourth and fifth (and to a lesser extent the first and second) toxin-binding regions overlapped with regions recognized by anti-(acetylcholine receptor) antibodies. The five toxin-binding regions may be distinct sites or, alternatively, different 'faces' in one (or more) sites. 相似文献