scholarly journals Genetic Organization and Molecular Analysis of the EcoVIII Restriction-Modification System of Escherichia coli E1585-68 and Its Comparison with Isospecific Homologs

2003 ◽  
Vol 69 (5) ◽  
pp. 2638-2650 ◽  
Author(s):  
Iwona Mruk ◽  
Tadeusz Kaczorowski
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Start Codon ◽  
Sequence Motif ◽  
Specific Sequence ◽  
Modification System ◽  
Acid Protein ◽  
Restriction Modification ◽  
Amino Acid Protein

ABSTRACT The EcoVIII restriction-modification (R-M) system is carried by the Escherichia coli E1585-68 natural plasmid pEC156 (4,312 bp). The two genes were cloned and characterized. The G+C content of the EcoVIII R-M system is 36.1%, which is significantly lower than the average G+C content of either plasmid pEC156 (43.6%) or E. coli genomic DNA (50.8%). The difference suggests that there is a possibility that the EcoVIII R-M system was recently acquired by the genome. The 921-bp EcoVIII endonuclease (R · EcoVIII) gene (ecoVIIIR) encodes a 307-amino-acid protein with an M r of 35,554. The convergently oriented EcoVIII methyltransferase (M · EcoVIII) gene (ecoVIIIM) consists of 912 bp that code for a 304-amino-acid protein with an M r of 33,930. The exact positions of the start codon AUG were determined by protein microsequencing. Both enzymes recognize the specific palindromic sequence 5′-AAGCTT-3′. Preparations of EcoVIII R-M enzymes purified to homogeneity were characterized. R · EcoVIII acts as a dimer and cleaves a specific sequence between two adenine residues, leaving 4-nucleotide 5′ protruding ends. M · EcoVIII functions as a monomer and modifies the first adenine residue at the 5′ end of the specific sequence to N 6-methyladenine. These enzymes are thus functionally identical to the corresponding enzymes of the HindIII (Haemophilus influenzae Rd) and LlaCI (Lactococcus lactis subsp. cremoris W15) R-M systems. This finding is reflected by the levels of homology of M · EcoVIII with M · HindIII and M · LlaCI at the amino acid sequence level (50 and 62%, respectively) and by the presence of nine sequence motifs conserved among m6 N-adenine β-class methyltransferases. The deduced amino acid sequence of R · EcoVIII shows weak homology with its two isoschizomers, R · HindIII (26%) and R · LlaCI (17%). A catalytic sequence motif characteristic of restriction endonucleases was found in the primary structure of R · EcoVIII (D108X12DXK123), as well as in the primary structures of R · LlaCI and R · HindIII. Polyclonal antibodies raised against R · EcoVIII did not react with R · HindIII, while anti-M · EcoVIII antibodies cross-reacted with M · LlaCI but not with M · HindIII. R · EcoVIII requires Mg(II) ions for phosphodiester bond cleavage. We found that the same ions are strong inhibitors of the M · EcoVIII enzyme. The biological implications of this finding are discussed.

scholarly journals The bglA Gene of Aspergillus kawachii Encodes Both Extracellular and Cell Wall-Bound β-Glucosidases

1999 ◽  
Vol 65 (12) ◽  
pp. 5546-5553 ◽  
Author(s):  
Kazuhiro Iwashita ◽  
Tatsuya Nagahara ◽  
Hitoshi Kimura ◽  
Makoto Takano ◽  
Hitoshi Shimoi ◽  
...  
Keyword(s):  
Cell Wall ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Amino Acid Sequences ◽  
Enzyme Assays ◽  
Partial Amino Acid Sequence ◽  
Reading Frame ◽  
Acid Protein ◽  
Aspergillus Kawachii ◽  
Amino Acid Protein

ABSTRACT We cloned the genomic DNA and cDNA of bglA, which encodes β-glucosidase in Aspergillus kawachii, based on a partial amino acid sequence of purified cell wall-bound β-glucosidase CB-1. The nucleotide sequence of the cloned bglA gene revealed a 2,933-bp open reading frame with six introns that encodes an 860-amino-acid protein. Based on the deduced amino acid sequence, we concluded that the bglA gene encodes cell wall-bound β-glucosidase CB-1. The amino acid sequence exhibited high levels of homology with the amino acid sequences of fungal β-glucosidases classified in subfamily B. We expressed the bglA cDNA inSaccharomyces cerevisiae and detected the recombinant β-glucosidase in the periplasm fraction of the recombinant yeast.A. kawachii can produce two extracellular β-glucosidases (EX-1 and EX-2) in addition to the cell wall-bound β-glucosidase.A. kawachii in which the bglA gene was disrupted produced none of the three β-glucosidases, as determined by enzyme assays and a Western blot analysis. Thus, we concluded that thebglA gene encodes both extracellular and cell wall-bound β-glucosidases in A. kawachii.

scholarly journals Ribosomal proteins L34 and S29 of amphioxus Branchiostoma belcheri tsingtauense: cDNAs cloning and gene copy number.

2005 ◽  
Vol 52 (4) ◽  
pp. 857-862 ◽  
Author(s):  
Lina Liu ◽  
Shicui Zhang ◽  
Zhenhui Liu ◽  
Hongyan Li ◽  
Mei Liu ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Ribosomal Proteins ◽  
Amino Acid Sequence Identity ◽  
Fruit Fly ◽  
Calculated Molecular Mass ◽  
Sequence Identity ◽  
Acid Protein ◽  
Branchiostoma Belcheri ◽  
Amino Acid Protein

The complete cDNA and deduced amino-acid sequences of ribosomal proteins L34 (AmphiL34) and S29 (AmphiS29) from the amphioxus Branchiostoma belcheri tsingtauense were identified in this study. The AmphiL34 cDNA is 435 nucleotides in length and encodes a 118 amino-acid protein with calculated molecular mass of 13.6 kDa. It shares 53.6-67.5% amino-acid sequence identity with its eukaryotic counterparts including human, mouse, rat, pig, frog, catfish, fruit fly, mosquito, armyworm, nematode and yeast. The AmphiS29 cDNA comprises 453 nucleotides and codes for a 56 amino-acid protein with a calculated molecular mass of 6.6 kDa. It shows 66.1-78.6% amino-acid sequence identity to eukaryotic S29 proteins from human, mouse, rat, pig, zebrafish, seahorse, fruit fly, nematode, sea hare and yeast. AmphiL34 contains a putative nucleolar localization signal, while AmphiS29 has a zinc finger-like domain. A phylogenetic tree deduced from the conserved sequences of AmphiL34 and AmphiS29 and other known counterparts indicates that the positions of AmphiL34/AmphiS29 are intermediate between the vertebrate and invertebrate L34/S29. Southern blot analysis demonstrates the presence of one copy of the L34 gene and 2-3 copies of the S29 gene in the genome of the amphioxus B. belcheri tsingtauense. This is in sharp contrast to the existence of 7-9 copies of the L34 gene and 14-17 copies of the S29 gene in the rat genome. These date suggest that housekeeping genes like AmphiL34 and AmphiS29 have undergone large-scale duplication in the chordate lineage.

scholarly journals Molecular and immunological characterization and IgE epitope mapping of Pen n 18, a major allergen of Penicillium notatum

2002 ◽  
Vol 363 (3) ◽  
pp. 707-715 ◽  
Author(s):  
Chia-Jung YU ◽  
Yen-Ming CHEN ◽  
Song-Nan SU ◽  
Farhad FOROUHAR ◽  
Shu-Hua LEE ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Serine Proteases ◽  
Major Allergen ◽  
Penicillium Notatum ◽  
Ige Binding ◽  
Acid Protein ◽  
Binding Epitope ◽  
Cross Inhibition ◽  
Amino Acid Protein

The mould genus, Penicillium, is a significant source of environmental aero-allergens. A major allergen from Penicillium notatum, Pen n 18, was identified by two-dimensional immunoblotting using monoclonal antibody G11A10, raised against the vacuolar serine protease of Penicillium citrinum, followed by matrix-assisted laser-desorption ionization—time-of-flight MS analysis of the peptide digest. Pen n 18 was then cloned and the amino acid sequence deduced from the cDNA sequence. The cDNA encoded a 494 amino acid protein, considerably larger than mature Pen n 18, the differences being due to the N- and C-terminal prosequences. The deduced amino acid sequence showed extensive similarity with those of vacuolar serine proteases from various fungi. The Pen n 18 coding sequence was expressed in Escherichia coli as a His-tagged fusion protein and purified by Ni2+-chelate affinity chromatography. On immunoblots, the purified recombinant protein specifically bound IgE from mould-allergic patients, and cross-inhibition assays demonstrated the presence of common IgE-binding epitopes on Pen n 18 and a major allergen of P. citrinum, Pen c 18. When mapping of the allergenic epitopes was performed, at least nine different linear IgE-binding epitopes, located throughout the Pen n 18 protein, were identified. Of these, peptide C12, located in the N-terminal region of the molecule, was recognized by serum from 75% of the patients tested and therefore appears to be an immunodominant IgE-binding epitope.

scholarly journals ICAP-1, a Novel β1 Integrin Cytoplasmic Domain–associated Protein, Binds to a Conserved and Functionally Important NPXY Sequence Motif of β1 Integrin

1997 ◽  
Vol 138 (5) ◽  
pp. 1149-1157 ◽  
Author(s):  
David D. Chang ◽  
Carol Wong ◽  
Healy Smith ◽  
Jenny Liu
Keyword(s):  
Cell Adhesion ◽  
Amino Acid ◽  
Cytoplasmic Domain ◽  
Sequence Motif ◽  
Β1 Integrin ◽  
Cytoplasmic Domains ◽  
Matrix Interaction ◽  
Cell Matrix ◽  
Acid Protein ◽  
Amino Acid Protein

The cytoplasmic domains of integrins are essential for cell adhesion. We report identification of a novel protein, ICAP-1 (integrin cytoplasmic domain– associated protein-1), which binds to the β1 integrin cytoplasmic domain. The interaction between ICAP-1 and β1 integrins is highly specific, as demonstrated by the lack of interaction between ICAP-1 and the cytoplasmic domains of other β integrins, and requires a conserved and functionally important NPXY sequence motif found in the COOH-terminal region of the β1 integrin cytoplasmic domain. Mutational studies reveal that Asn and Tyr of the NPXY motif and a Val residue located NH2-terminal to this motif are critical for the ICAP-1 binding. Two isoforms of ICAP-1, a 200–amino acid protein (ICAP-1α) and a shorter 150–amino acid protein (ICAP-1β), derived from alternatively spliced mRNA, are expressed in most cells. ICAP-1α is a phosphoprotein and the extent of its phosphorylation is regulated by the cell–matrix interaction. First, an enhancement of ICAP-1α phosphorylation is observed when cells were plated on fibronectin-coated but not on nonspecific poly-l-lysine–coated surface. Second, the expression of a constitutively activated RhoA protein that disrupts the cell–matrix interaction results in dephosphorylation of ICAP-1α. The regulation of ICAP-1α phosphorylation by the cell–matrix interaction suggests an important role of ICAP-1 during integrin-dependent cell adhesion.

scholarly journals Genetic Organization and Mode of Action of a Novel Bacteriocin, Bacteriocin 51: Determinant of VanA-Type Vancomycin-Resistant Enterococcus faecium

2011 ◽  
Vol 55 (9) ◽  
pp. 4352-4360 ◽  
Author(s):  
Hitoshi Yamashita ◽  
Haruyoshi Tomita ◽  
Takako Inoue ◽  
Yasuyoshi Ike
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Enterococcus Faecium ◽  
Promoter Sequence ◽  
Signal Peptidase ◽  
Start Codon ◽  
Content Type ◽  
Acid Protein ◽  
Vancomycin Resistant ◽  
Amino Acid Protein

ABSTRACTBacteriocin 51 (Bac 51) is encoded on the mobile plasmid pHY (6,037 bp), which was isolated from vancomycin-resistantEnterococcus faeciumVRE38. Bacteriocin 51 is active againstE. faecium,E. hirae, andE. durans. Sequence analysis of pHY showed that it encodes nine open reading frames (ORFs) from ORF1 to ORF9 (in that order). Genetic analysis suggested that ORF1 and ORF2, which were designatedbacAandbacB, respectively, are the bacteriocin and immunity genes.bacAencodes a 144-amino-acid protein. The deduced BacA protein has a typical signal sequence at its amino terminus, and a potential signal peptidase-processing site corresponding to the V-E-A sequence is located between the 37th and 39th amino acids. The predicted mature BacA protein consists of 105 amino acids. A potential promoter sequence was identified upstream of the start codon.bacBencodes a 55-amino-acid protein. No obvious promoter or terminator sequence was identified betweenbacAandbacB. Northern blot analysis ofbacAandbacBwith abacARNA probe produced a transcript of approximately 700 nucleotides, which corresponded to the combined nucleotide sizes ofbacAandbacB, indicating that transcription was initiated from the promoter upstream ofbacA, continued throughbacB, and was terminated at the terminator downstream ofbacB. The transcription start site was determined to be the T nucleotide located 6 nucleotides downstream from the −10 promoter sequence. These results indicate thatbacAandbacBconstitute an operon and thatbacAis the bacteriocin structural gene whilebacBis the immunity gene. The purified C-terminally His tagged BacA protein of Bac 51 showed bacteriostatic activity against the indicator strain. The purified C-terminally His tagged BacA protein of Bac 32 (whose mature BacA protein has 54 amino acids) and the culture filtrates of the Bac 31- and Bac 43-producingE. faecalisstrain FA2-2 showed bactericidal activity. Bac 31 and Bac 43 are pore-forming bacteriocins, unlike the newly characterized bacteriocin Bac 51.

Characterization of the LlaCI methyltransferase from Lactococcus lactis subsp. cremoris W15 provides new insights into the biology of type II restriction–modification systems

Microbiology ◽  
2003 ◽  
Vol 149 (11) ◽  
pp. 3331-3341 ◽  
Author(s):  
Iwona Mruk ◽  
Magdalena Cichowicz ◽  
Tadeusz Kaczorowski
Keyword(s):  
Escherichia Coli ◽  
Lactococcus Lactis ◽  
Start Codon ◽  
Sequence Motifs ◽  
Amino Acid Sequence Level ◽  
Specific Sequence ◽  
Strong Inhibitor ◽  
Apparent Homogeneity ◽  
Restriction Modification ◽  
Restriction Modification Systems

The gene encoding the LlaCI methyltransferase (M.LlaCI) from Lactococcus lactis subsp. cremoris W15 was overexpressed in Escherichia coli. The enzyme was purified to apparent homogeneity using three consecutive steps of chromatography on phosphocellulose, blue-agarose and Superose 12HR, yielding a protein of M r 31 300±1000 under denaturing conditions. The exact position of the start codon AUG was determined by protein microsequencing. This enzyme recognizes the specific palindromic sequence 5′-AAGCTT-3′. Purified M.LlaCI was characterized. Unlike many other methyltransferases, M.LlaCI exists in solution predominantly as a dimer. It modifies the first adenine residue at the 5′ end of the specific sequence to N 6-methyladenine and thus is functionally identical to the corresponding methyltransferases of the HindIII (Haemophilus influenzae Rd) and EcoVIII (Escherichia coli E1585-68) restriction–modification systems. This is reflected in the identity of M.LlaCI with M.HindIII and M.EcoVIII noted at the amino acid sequence level (50 % and 62 %, respectively) and in the presence of nine sequence motifs conserved among N 6-adenine β-class methyltransferases. However, polyclonal antibodies raised against M.EcoVIII cross-reacted with M.LlaCI but not with M.HindIII. Restriction endonucleases require Mg2+ for phosphodiester bond cleavage. Mg2+ was shown to be a strong inhibitor of the M.LlaCI enzyme and its isospecific homologues. This observation suggests that sensitivity of the M.LlaCI to Mg2+ may strengthen the restriction activity of the cognate endonuclease in the bacterial cell. Other biological implications of this finding are also discussed.

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