首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Thyroid-stimulating hormone (TSH) beta subunit cDNA was obtained from Japanese quail (Coturnix japonica) by PCR and its nucleotide sequence was determined. The cDNA encodes a putative signal peptide and a mature protein consisting of 20 and 114 amino acids, respectively. The amino acid sequence of quail TSHbeta subunit shows homologies of 67-69% in mammalian species, 58% in amphibian and 43-49% in teleost fish. Comparison of the amino acid sequence with TSHbeta subunits of other species reveals some differences in several regions responsible for its biological functions and characteristic features of the avian TSHbeta subunit, suggesting that the functional domains have diverged cooperatively between the hormone and its receptor during evolution.  相似文献   

2.
3.
The gene of capillary permeability-increasing enzyme-2 (CPI enzyme-2) was cloned from the cDNA library of Agkistrodon caliginosus and its nucleotide sequence was determined. Its sequence indicates that CPI enzyme-2 is synthesized as a pre-zymogen of 258 amino acid residues, including a putative secretory signal peptide of 18 amino acids and a proposed zymogen peptide of 6 amino acids. The amino terminal sequence deduced from the cDNA sequence was exactly consistent with that of CPI enzyme-2 except for the substitution of an amino acid (Gly27-->Ser). The open reading frame is very similar to those of plasminogen activator and thrombin-like proteases cloned from other snakes. The clone encoding CPI enzyme-2 belongs to the serine protease family. The active site of the enzyme is highly conserved at His41, Asp86 and Ser180. Its possible glycosylation sites, Asn-X-Thr/Ser, are located at amino acid residues 20-22, 55-57, 79-81 and 97-99.  相似文献   

4.
Two forms of a proteinase, KN-BJ 1 and 2, were purified to homogeneity from the venom of Bothrops jararaca. In SDS/PAGE reduced KN-BJ 1 and 2 migrated as single bands with molecular masses of 38 kDa and 39 kDa. The two enzymes have similar N-terminal amino acid sequences and specific activities on synthetic chromogenic substrates, and both release bradykinin from bovine low-molecular-mass kininogen. KN-BJ 1 and KN-BJ 2 clot fibrinogen with specific activities of 245 NIH U/mg and 219 NIH U/mg, releasing only fibrinopeptide A. The amidolytic, kinin-releasing and coagulant activities are inhibited by phenylmethylsulfonyl fluoride, demonstrating that KN-BJ is a serine proteinase. Benzamidine derivatives, which are competitive inhibitors of trypsin-like proteinases, also inhibited the amidolytic activity of KN-BJ. A cDNA clone (HS104, 2.2 kb) has been isolated from a cDNA library of B. jararaca venom glands with an ORF of 771 bp. The deduced amino acid sequence contains segments that are identical to the sequences of the N-terminus and three tryptic peptides of KN-BJ 2. Therefore, the cDNA is believed to represent the gene of KN-BJ 2. The deduced amino acid sequence indicates that KN-BJ 2 is synthesized as a prezymogen of 257 amino acids with a putative signal peptide of 18 amino acids and an activating peptide of six amino acid residues. The sequence of 233 amino acids representing the mature enzyme exhibits high similarity to sequences of serine proteinases isolated from crotalid venoms.  相似文献   

5.
6.
A cDNA of amine sulfotransferase-RB1 (AST-RB1), which efficiently catalyzes 4-phenyl-1,2,3,6-tetrahydropyridine (PTHP) sulfation, has been isolated by immunoscreening of a rabbit liver cDNA library. The cDNA consisted of 1,117 base pairs and encoded a protein of 301 amino acids with a molecular weight of 35,876. The deduced amino acid sequence matched at six positions those of peptide fragments obtained from purified AST-RB1 protein. The sequence had less than 38% identity at the amino acid level with cytosolic sulfotransferases in mammals, although high degrees of similarity were observed with regions conserved throughout mammalian sulfotransferases. These results indicate that AST-RB1, arbitrarily named sulfotransferase 3A1 (ST3A1), constitutes a new and third gene family of cytosolic sulfotransferases in mammals. ST3A1 expressed in Escherichia coli as a fused protein catalyzed sulfation of amines such as PTHP, aniline, 4-chloroaniline, 2-naphthylamine, and desipramine, but barely O-sulfation of typical aryl and hydroxysteroid sulfotransferase substrates. These data unequivocally demonstrate the existence of a cytosolic sulfotransferase showing a high selectivity for amine substrates, and indicate that multiple forms of sulfotransferase mediate sulfation of xenobiotics in mammalian livers.  相似文献   

7.
Sialidase L is a NeuAcalpha2-->3Gal linkage-specific sialidase that releases 2,7-anhydro-NeuAc instead of NeuAc from sialoglycoconjugates (Chou, M.-Y., Li, S.-C., Kiso, M., Hasegawa, A., and Li, Y.-T.(1994) J. Biol. Chem. 269, 18821-18826). A 2. 5-kilobase cDNA of sialidase L was cloned by a combination of methods based on polymerase chain reactions. The composite cDNA sequence reveals an open reading frame coding for 762 amino acids, including a putative 28-residue signal peptide at the N terminus that is similar to the signal sequence of the Clostridium septicum sialidase. The result suggests that sialidase L is a secretory enzyme. The coding sequence excluding the putative signal peptide of sialidase L was overexpressed in Escherichia coli. The purified recombinant enzyme was characterized to be as active as the enzyme isolated from the leech. It also possessed the strict NeuAcalpha2-->3Gal linkage specificity and released the unique cleavage product, 2,7-anhydro-NeuAc from sialoglycoconjugates. The deduced amino acid sequence of sialidase L exhibits little similarity with other reported sialidases. However, sialidase L contains a conserved "FRIP region" and four repeating "Asp box" motifs that align well with the corresponding positions of bacterial sialidases. The predicted beta-strand structures near the conserved motifs of sialidase L are similar to those of Salmonella typhimurium sialidase. Several conserved single amino acid residues of bacterial sialidases, including those known to be involved in the active site of Salmonella enzyme, are conserved in the deduced amino acid sequence of sialidase L. This observation suggests that part of the catalytic mechanism of sialidase L may be similar to the ordinary sialidase.  相似文献   

8.
The nucleotide sequences of 3 cDNA clones corresponding to entire RNA genome of bean common mosaic virus NL3 strain have been determined. The RNA is 9612 nucleotides long, excluding a 3'-terminal poly(A) tail. A putative start codon located at nucleotide positions 170-172 initiates one large open reading frame that is terminated with a UAA codon at position 9368-9370. The predicted polyprotein has 3066 amino acids and an M(r) of 340.3 kDa. The positions of putative protein cleavage sites have been determined by analogy to consensus sequences in other potyviruses. The nucleotide sequences of the non-translated regions and the predicted amino acid sequences of BCMV NL3, were compared with those of other potyviruses. Comparison of the BCMV NL3 proteins with those of other potyviruses indicated a similar genomic organization, and high percentage of amino acid sequence identity in the cylindrical inclusion protein, nuclear inclusion 'b' protein and coat protein. BCMV NL3 displays the highest amino acid sequence identity with soybean mosaic virus.  相似文献   

9.
We recently cloned a new leukemogenesis-associated gene MmTRA1a (Mm-1 cell derived transplantability-associated gene 1a, former name "TRA1") from a mouse leukemogenic and monocytic Mm-P cell cDNA library and also cloned its normal counterpart MmTRA1b (former name "NOR1") from a normal mouse kidney cDNA library. The mouse MmTRA1a is a truncated form of mouse MmTRA1b. Here we report the cloning of a cDNA (human MmTRA1b) homologous to the mouse MmTRA1b from a human monocytic U937 cell cDNA library. The human MmTRA1b cDNA predicts a peptide containing 318 amino acids with a calculated molecular weight of 35,047 Da. The predicted human MmTRA1b protein sequence shared 78% amino acid identity with the mouse counterpart (328 amino acids). Both the human homologue and mouse MmTRA1b protein but not MmTRA1a protein possess a proline-rich domain at the N-terminal end. The human MmTRA1b gene was mapped to chromosome 3q23. Expression of the human homologue was increased during differentiation of U937 cells induced by most typical differentiation inducers. Moreover, predicted amino acid sequence analysis of human MmTRA1b cDNA revealed perfect identity with the human plasma membrane phospholipid scramblase that is required for transbilayer movement of membrane phospholipids. These results provide new information on the possible roles of MmTRA1b/phospholipid scramblase and the truncated MmTRA1a in the leukemogenesis and differentiation of monocytic leukemia cells.  相似文献   

10.
The genes encoding the envelope glycoprotein H (gH) and gB homologues were identified by sequencing genomic clones of human herpesvirus-7 (HHV-7), strain JI. A gB cDNA clone from HHV-7 strain AL was also identified. The deduced primary translation products of the gH and gB genes are a protein of 690 amino acids, with a predicted mass of 80.4 kD, and a protein of 822 amino acids, with a predicted mass of 93.3 kD, respectively. Both the predicted proteins have the characteristics of transmembrane glycoproteins, containing signal and transmembrane sequence motifs and characterized by the presence of 10 (gH) and 11 (gB) potential motifs for N-glycosylation. Comparison of amino acid sequence of HHV-7 gH and gB with the homologous sequences of the other human herpesviruses reveals closest homology with HHV-6 (38.8% identity for gH, 56.2% identity for the gB). In addition, significant sequence similarity was also observed between the gH and gB of HHV-7 and the homologs encoded by human cytomegalovirus (21.6% identity for gH, 37.6% identity for gB). No significant differences existed between the gB sequence of the two different HHV-7 strains analyzed. The products of the HHV-7 gH and gB expressed transiently in eukaryotic cells were specifically recognized by an HHV-7-reactive human serum in immunofluorescence assays.  相似文献   

11.
Here we describe the cloning of a full-length cDNA encoding a neutrophil chemoattractant peptide, ENA-78, from human platelets. The cDNA encodes a predicted sequence of 114 amino acids and contains the Cys motif C-X-C found in other members of the alpha-chemokine family which also includes interleukin 8 (IL-8). ENA-78 has a high degree of sequence identity with other platelet-derived chemokines which also share overlapping chemotactic activities such as GRO alpha and the neurophil-activating peptide 2 (NAP-2; derived by proteolytic cleavage of the connective-tissue-activating peptide III (CTAP-III)).  相似文献   

12.
Partial complementary DNA (cDNA) for thymidine phosphorylase (dThdPase) was cloned by means of a polymerase chain reaction. There was complete sequence identity between the amino acid sequence deduced from the nucleotide sequence of a clone (288 nucleotides) and the residues of platelet-derived endothelial cell growth factor (PD-ECGF). The amino acid sequence of all four peptide fragments from purified human dThdPase could be aligned with that of PD-ECGF. Our data indicate that residues 125-244 of PD-ECGF are identical to the sequence of human dThdPase. The molecular weights of human dThdPase and recombinant PD-ECGF (rPD-ECGF) that lacks 10 amino acids at the amino terminal were 55 and 52 kDa, respectively. Anti-PD-ECGF antibody recognized dThdPase, and anti-dThdPase antibody recognized rPD-ECGF. rPD-ECGF had dThdPase activity and its specific activity was similar to that of purified human dThdPase. dThdPase activity and molecules were detected in COS cells transfected with human PD-ECGF cDNA, but not in nontransfected cells. The sizes of PD-ECGF and dThdPase in the transfected COS cells were identical. These data suggest that human dThdPase is identical to PD-ECGF.  相似文献   

13.
Insulin-like growth factor-II (IGF-II) is a fetal growth factor in humans, but has not been clearly identified in fish up to now. For a detailed understanding of the physiological response of fish IGF-II, the first step was to clone tilapia IGF-II cDNA from the brain cDNA library, coding the region of genomic DNA, and also expressing tilapia IGF-II polypeptides from Escherichia coli. Tilapia cDNA sequences total 1,977 bp, and predicted nucleotide sequences and amino acid sequences of tilapia share 77.9% and 90.7% homology identity with rainbow trout IGF-II, respectively. The genomic structure of the tilapia prepro-IGF-II coding region is very difficult to sequence in mammals and birds. The cloned tilapia IGF-II gene coding region appears much more complex than in other vertebrates. In tilapia IGF-II, the first coding exon I encoding part of the signal peptide sequence is 25 amino acids shorter than the first coding exon of mammals and birds. The other 23 amino acids of the signal peptide, and the first amino acids of the B domain and C domain are encoded by tilapia coding exon 2. The C, A, and D domains, and the first 20 amino acids of the E peptide are encoded by tilapia coding exon 3. The other E peptides and the 3' untranslated region (UTR) region are encoded by tilapia coding exon 4. These data show that the IGF-II genes have significantly differing structures in vertebrate evolution, and there are differences of interrupting introns in the IGF-I genomic structure compared with mammals. To obtain recombinant biologically active polypeptides, tilapia IGF-II B-C-A-D domains were amplified using the polymerase chain reaction (PCR), then ligated with glutathione S-transferase (GST, pGEX-2T vector). Tilapia recombinant IGF-II protein was purified and characterized in E. coli. The fusion protein was also digested with thrombin and appeared as a recombinant IGF-II polypeptide single band with a molecular mass of 7 kD. The recombinant tilapia IGF-II protein biological function was measured by stimulation of [3H]thymidine incorporation. The assay concentration was set up from 0 to 120 nM to stimulate tilapia ovary cell line (TO-2) significantly to uptake thymidine. The results suggest that the recombinant IGF-II protein was dose dependent.  相似文献   

14.
The present study examines the similarity in the symptoms and binding properties between the depressant and excitatory insect-selective neurotoxins, derived from scorpion venom. A comparison of their primary structures and neuromuscular effects is presented. A new depressant toxin (LqhIT2) was purified from the venom of the scorpion Leiurus quinquestriatus hebraeus. The effects of this toxin on a prepupal housefly neuromuscular preparation mimic its effects on the intact insect, i.e, a brief period of repetitive bursts of regular junction potentials (JPs) is followed by reduced amplitude JPs ending with a block of the neuromuscular transmission. "Loose" patch clamp recordings indicate that the repetitive activity has a presynaptic origin (the motor nerve) and resembles the effect of the excitatory toxin AaIT. The final synaptic block is supposed to be the end result of neuronal membrane depolarization. Such an effect is not caused by an excitatory toxin, which induces long "trains" of repetitive firing. The amino acid sequences of three depressant toxins were determined by automatic Edman degradation indicating a high degree of sequence homology. This conservation differs from those of other groups of scorpion toxins. The opposing pharmacological effects of depressant toxins are discussed in light of the above neuromuscular effects and sequence analysis. A genetic approach in the study of the structure-function relationships of the depressant toxins was initiated by isolating cDNA clones encoding the LqhIT2 and BjIT2 toxins. Their sequence analysis revealed the precursor form of these toxins: A 21 amino acid residue signal peptide followed by a 61 amino acid region of the mature toxin, and three additional amino acids at the carboxy terminus.  相似文献   

15.
16.
Amadoriase is an enzyme catalyzing the oxidative deglycation of Amadori products to yield corresponding amino acids, glucosone, and H2O2. We previously reported the purification and characterization of two amadoriase isozymes from Aspergillus sp. that degrade both glycated low molecular weight amines and amino acids (Takahashi, M., Pischetsrieder, M., and Monnier, V. M. (1997) J. Biol. Chem. 272, 3437-3443). To identify the primary structure of the enzymes, we have prepared a cDNA library from Aspergillus fumigatus induced with fructosyl propylamine and isolated a clone using polyclonal anti-amadoriase II antibody. The primary structure of the enzyme deduced from the nucleotide sequence comprises 438 amino acid residues with a predicted molecular mass of 48,798 Da. The deduced primary structure exhibits the presence of an ADP-binding motif near the NH2 terminus. The identity of the amadoriase II cDNA was further confirmed by expression in Escherichia coli cells with an inducible expression system. Northern blotting analysis revealed that amadoriase II was induced by fructosyl propylamine in a dose-dependent manner.  相似文献   

17.
We have used Arabidopsis calmodulin (CaM) covalently coupled to horseradish peroxidase to screen a barley aleurone cDNA expression library for CaM binding proteins. The deduced amino acid sequence of one cDNA obtained by this screen was shown to be a unique protein of 702 amino acids with CaM and cyclic nucleotide binding domains at the carboxyl terminus and high similarity to olfactory and K+ channels. This cDNA was designated HvCBT1 (Hordeum vulgare CaM binding transporter). Hydropathy plots of HvCBT1 showed the presence of six putative transmembrane domains, but sequence alignment indicated a pore domain that was unlike the consensus domains in K+ and olfactory channels. Expression of a subclone of amino acids 482-702 in Escherichia coli generated a peptide that bound CaM. When a fusion protein of HvCBT1 and green fluorescent protein was expressed in barley aleurone protoplasts, fluorescence accumulated in the plasma membrane. Expression of HvCBT1 in the K+ transport deficient Saccharomyces cerevisiae mutant CY162 showed no rescue of the mutant phenotype. However, growth of CY162 expressing HvCBT1 with its pore mutated to GYGD, the consensus sequence of K+ channels, was compromised. We interpret these data as indicating that HvCBT1 acts to interfere with ion transport.  相似文献   

18.
PURPOSE: Patients with active pars planitis have increased levels of a 36 kDa protein (p-36) in their circulation. The current studies were undertaken to determine the primary structure of this protein. METHODS: A degenerate oligonucleotide probe based on the amino terminal sequence of p-36 was used to identify a clone from a human spleen cDNA library. The cDNA insert was subcloned into the EcoR1 site of pUC-19, and both strands were sequenced. Southern blot analysis was used to study the genomic hybridization pattern. p-36 cDNA was subcloned in a pSG5 expression vector, and the construct was used to transfect COS-7 cells. RESULTS: The cDNA sequence contained an open reading frame of 966 base pairs encoding a protein of 322 amino acids, an untranslated region of 322 base pairs, and 2693 base pairs at the 5' and 3' ends, respectively. The deduced amino acid sequence showed 96.8% identity with the carboxy-terminal region of a yeast nucleopore complex protein, nup 100. Southern blot analysis of human genomic DNA revealed a simple hybridization pattern. Transfection of p-36 cDNA in COS-7 cells resulted in the presence of p-36 mRNA and expression of protein. CONCLUSIONS: The 36 kDa protein (p-36) detected at increased levels in the blood of patients with active pars planitis was cloned from a human spleen cDNA library. Its deduced amino acid sequence is homologous with the carboxy-terminal region of a nucleopore complex protein. Thus, we refer to this protein as nup36.  相似文献   

19.
A cDNA clone, called CLB1, was isolated from a cDNA library from tomato (Lycopersicon esculentum) and characterized. The CLB1 cDNA contains an open reading frame of 1518 bp, and encodes a putative protein of 506 amino acids with a predicted molecular mass of 54,633 Da. The deduced CLB1 amino acid sequence contains a domain that exhibits from 26% to 37% identity with the Ca2+-dependent lipid-binding domains of cytosolic phospholipase A2, protein kinase C, Rabphilin-3A, and Synaptotagmin 1 of animals. Southern blot analysis indicates that the CLB1 gene belongs to a small gene family in the tomato genome. The CLB1 mRNA is preferentially expressed in fruit tissues.  相似文献   

20.
A full length cDNA for rkST1, a novel member of the Na+/glucose cotransporter family, was cloned from rabbit kidney and sequenced. The coding sequence comprised 2022 base pairs and 674 amino acids. rkST1 beared 50-60% amino acid identity to the other cotransporters and was characteristic in respect of its expression in brain in addition to kidney among the cotransporters.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号