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We have cloned and expressed in Escherichia coli a gene encoding a 15,000-apparent-molecular-weight peptidoglycan-associated outer membrane lipoprotein (PAL) of Haemophilus influenzae. The nucleotide sequence of this gene encodes an open reading frame of 153 codons with a predicted mature protein of 134 amino acids. The amino acid composition and sequence of the predicted mature protein agree with the chemically determined composition and partial amino acid sequence of PAL purified from H. influenzae outer membranes. We have also identified a second gene from H. influenzae that encodes a second 15,000-apparent-molecular-weight protein which is recognized by antiserum against PAL. This protein has been shown to be a lipoprotein. The nucleotide sequence of this gene encodes an open reading frame of 154 codons with a predicted mature protein of 136 amino acids and has limited sequence homology with that of the gene encoding PAL. Southern hybridization analysis indicates that both genes exist as single copies in H. influenzae chromosomal DNA. Both genes encode polypeptides which have amino-terminal sequences similar to those of reported membrane signal peptides and are associated primarily with the outer membrane when expressed in E. coli.  相似文献   

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Two DNA fragments, 3 kbp and 7.8kbp, which encode the type C1 botulinum neurotoxin gene, were obtained from toxigenic bacteriophage DNA by treatment with a restriction enzyme. They were cloned into the plasmid vectors for nucleotide sequence determination. The nucleotide sequence contained a single open reading frame coding for 1,291 amino acids corresponding to a polypeptide with a molecular weight of 149,000. The amino acid sequence of the C1 toxin has a few regions highly homologous with tetanus toxin.  相似文献   

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A pool of synthetic oligonucleotides was used to identify the gene encoding tetanus toxin on a 75-kbp plasmid from a toxigenic non-sporulating strain of Clostridium tetani. The nucleotide sequence contained a single open reading frame coding for 1315 amino acids corresponding to a polypeptide with a mol. wt of 150,700. In the mature toxin molecule, proline (2) and serine (458) formed the N termini of the 52,288 mol. wt light chain and the 98,300 mol. wt heavy chain, respectively. Cysteine (467) was involved in the disulfide linkage between the two subchains. The amino acid sequences of the tetanus toxin revealed striking homologies with the partial amino acid sequences of botulinum toxins A, B, and E, indicating that the neurotoxins from C. tetani and C. botulinum are derived from a common ancestral gene. Overlapping peptides together covering the entire tetanus toxin molecule were synthesized in Escherichia coli and identified by monoclonal antibodies. The promoter of the toxin gene was localized in a region extending 322 bp upstream from the ATG codon and was shown to be functional in E. coli.  相似文献   

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The nucleotide sequence of the gene (tnpA) which codes for the transposase of transposon Tn501 has been determined. It contains an open reading frame for a polypeptide of Mr = 111,500, which terminates within the inverted repeat sequence of the transposon. The reading frame would be transcribed in the same direction as the mercury-resistance genes and the tnpR gene. The amino acid sequence predicted from this reading frame shows 32% identity with that of the transposase of the related transposon Tn3. The C-terminal regions of these two polypeptides show slightly greater homology than the N-terminal regions when conservative amino acid substitutions are considered. With this sequence determination, the nucleotide sequence of Tn501 is fully defined. The main features of the sequence are briefly presented.  相似文献   

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The gene gyrA of Escherichia coli, which encodes the A subunit of DNA gyrase (topoisomerase II), has been cloned and a region of approximately 3300 base-pairs sequenced. An open reading frame of 2625 nucleotides coding for a protein of 97,000 Mr is located. The peptide weight of the subunit predicted from this open reading frame is in close agreement with previously published estimates of that of the A subunit. There is a "TATAAT" promoter motif located 44 bases upstream from the first "ATG" of the open reading frame. The amino acid sequence derived from the nucleotide sequence is about 50% homologous with that derived from the Bacillus subtilis gyrA gene sequence, with several regions showing greater than 90% homology.  相似文献   

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The nucleotide sequence of the UL31 open reading frame is predicted to encode a basic protein with a hydrophilic amino terminus and a nuclear localization signal. To identify its gene product, we constructed a viral genome in which the thymidine kinase gene was inserted between the UL31 and UL32 open reading frames. The thymidine kinase gene was then deleted, and in the process, the 5' terminus of the UL31 open reading frame was replaced with a 64-bp sequence in frame with the complete, authentic sequence of the UL31 open reading frame. The inserted sequence encoded a hydrophilic epitope derived from glycoprotein B of human cytomegalovirus and for which a monoclonal antibody is available. We report that in infected cells, the tagged protein localized in and was dispersed throughout the nucleus. Nuclear fractionation studies revealed that the UL31 protein partitions with the nuclear matrix. The protein is phosphorylated in infected cells maintained in medium containing 32Pi.  相似文献   

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The nucleotide sequence of a 2.1-kilobase-pair fragment containing the Streptomyces choA gene, which codes a secreted cholesterol oxidase, was determined. A single open reading frame encodes a mature cholesterol oxidase of 504 amino acids, with a calculated Mr of 54,913. The leader peptides extend over 42 amino acids and have the characteristics of a signal sequence, including basic amino acids near the amino terminus and a hydrophobic core near the signal cleavage site. Analyses of the total amino acid composition and amino acid sequencing of the first 21 amino acids from the N terminus of the purified extracellular enzyme agree with the values deduced from nucleotide sequencing data.  相似文献   

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The nucleotide sequence of a 2301 base pair region of Saccharomyces cerevisiae DNA containing the PHR1 gene is reported. Within this region a single open reading frame of 1695 base pairs was found; using the insertional inactivation technique it was shown that part or all of this open reading frame specifies the PHR1-encoded photolyase. The amino acid sequence of the 565 amino acid long polypeptide predicted from the PHR1 nucleotide sequence was compared to the amino acid sequence of E. coli photolyase. Overall the sequence homology was 36.5%; however, two short regions near the amino terminus as well as the carboxy-terminal 150 amino acids display significantly greater sequence homology. The presence of these strongly conserved regions suggests that the yeast and E. coli photolyase possess common structural and functional domains involved in substrate and/or chromophore binding.  相似文献   

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A biochemical, molecular, and genetic analysis of the Saccharomyces cerevisiae INO1 gene and its product, L-myo-inositol-1-phosphate synthase (EC 5.5.1.4) has been carried out. The sequence of the entire INO1 gene and surrounding regions has been determined. Computer analysis of the DNA sequence revealed four potential peptides. The largest open reading frame of 553 amino acids predicted a peptide with a molecular weight of 62,842. The amino acid composition and amino terminus of purified L-myo-inositol-1-phosphate synthase were chemically determined and compared to the amino acid composition and amino terminus of the protein predicted from the DNA sequence of the large open reading frame. This analysis established that the large open reading frame encodes L-myo-inositol-1-phosphate synthase. The largest of several small open reading frames adjacent to INO1 predicted a protein of 133 amino acids with a molecular weight of 15,182 and features which suggested that the encoded protein may be membrane-associated. A gene disruption was constructed at INO1 by eliminating a portion of the coding sequence and replacing it with another sequence. Strains carrying the gene disruption failed to express any protein cross-reactive to antibody directed against L-myo-inositol-1-phosphate synthase. Although auxotrophic for inositol, strains carrying the gene disruption were completely viable when supplemented with inositol. In a similar fashion, a gene disruption was constructed in the chromosomal locus of the 133-amino acid open reading frame. This mutation did not affect viability but did cause inositol to be excreted from the cell.  相似文献   

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Nucleotide sequence of the Bacillus subtilis phoR gene.   总被引:14,自引:9,他引:5       下载免费PDF全文
The nucleotide sequence of phoR, the positive and negative regulatory gene for alkaline phosphatase and phosphodiesterase formation in Bacillus subtilis, was determined. The sequence data predicted an open reading frame of 1,740 base pairs (579 amino acids) which overlaps the 5 base pairs of the preceding phoP coding sequence. The deduced amino acid sequence was significantly homologous with that of the Escherichia coli phoR gene product, which is the sensory element for the pho regulon.  相似文献   

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We have determined the complete nucleotide sequence of a 4.8 kilobase fragment encompassing the virA locus of the nopaline-type plasmid, pTiC58, of Agrobacterium tumefaciens. virA is composed of a single open reading frame of 2499 nucleotides, capable of encoding a protein of 91.3 kiloDaltons. A trpE::virA gene fusion was used to confirm the reading frame of virA. High nucleotide and amino acid sequence homologies were observed between pTiC58 virA and the virA sequences of three octopine-type plasmids. Strong homologies in amino acid sequence were observed between pTiC58 VirA and seven bacterial proteins which control various regulons. Two hydrophobic domains within VirA are also consistent with a model in which VirA acts as a membrane-bound sensor of plant signal molecules.  相似文献   

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Nucleotide sequence of the Bacillus subtilis developmental gene spoVE   总被引:4,自引:0,他引:4  
We have determined the nucleotide sequence of a 1159 bp DNA fragment containing the spoVE locus of Bacillus subtilis. The locus contained a single open reading frame of 293 codons. On the basis of the predicted amino acid sequence, the product of the spoVE gene is believed to be a protein with an Mr of 31,539. The amino-terminal portion of the spoVE gene was used to construct a translational fusion with the lacZ' gene. The hybrid spoVE-lacZ' gene was shown to be expressed in Escherichia coli and, therefore, it seems reasonable to conclude that the proposed open reading frame for the spoVE gene does indeed function in vivo.  相似文献   

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Primers designed to conserved regions of botulinum and tetanus clostridial toxins were used to amplify DNA fragments from non-proteolytic Clostridium botulinum type F (202F) DNA using polymerase chain reaction technology. The fragments were cloned and the complete nucleotide sequence of the gene encoding type F toxin determined. Analysis of the nucleotide sequence demonstrated the presence of an open frame encoding a protein of 1274 amino acids, similar to other botulinum neurotoxins. Upstream of the toxin gene is the end of an open reading frame which encodes the C-terminus of a protein with homology to non-toxic-non-hemagglutinin component of type C progenitor toxin.  相似文献   

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Sequence analysis of a substantial part of the polymerase gene of the murine coronavirus MHV-A59 revealed the 3' end of an open reading frame (ORF1a) overlapping with a large ORF (ORF1b; 2733 amino acids) which covers the 3' half of the polymerase gene. The expression of ORF1b occurs by a ribosomal frameshifting mechanism since the ORF1a/ORF1b overlapping nucleotide sequence is capable of inducing ribosomal frameshifting in vitro as well as in vivo. A stem-loop structure and a pseudoknot are predicted in the nucleotide sequence involved in ribosomal frameshifting. Comparison of the predicted amino acid sequence of MHV ORF1b with the amino acid sequence deduced from the corresponding gene of the avian coronavirus IBV demonstrated that in contrast to the other viral genes this ORF is extremely conserved. Detailed analysis of the predicted amino acid sequence revealed sequence elements which are conserved in many DNA and RNA polymerases.  相似文献   

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The galU gene of Escherichia coli, thought to encode the enzyme UTP:alpha-D-glucose-1-phosphate uridylyltransferase, had previously been mapped to the 27-min region of the chromosome (J. A. Shapiro, J. Bacteriol. 92:518-520, 1966). By complementation of the membrane-derived oligosaccharide biosynthetic defect of strains with a galU mutation, we have now identified a plasmid containing the galU gene and have determined the nucleotide sequence of this gene. The galU gene is located immediately downstream of the hns gene, and its open reading frame would be transcribed in the direction opposite that of the hns gene (i.e., clockwise on the E. coli chromosome). The nucleotide sequences of five galU mutations were also determined. The enzyme UTP:alpha-D-glucose-1-phosphate uridylyltransferase was purified from a strain containing the galU gene on a multicopy plasmid. The amino-terminal amino acid sequence (10 residues) of the purified enzyme was identical to the predicted amino acid sequence (after the initiating methionine) of the galU-encoded open reading frame. The functional enzyme appears to be a tetramer of the galU gene product.  相似文献   

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