scholarly journals New lnu(C) Gene Conferring Resistance to Lincomycin by Nucleotidylation in Streptococcus agalactiae UCN36

2005 ◽  
Vol 49 (7) ◽  
pp. 2716-2719 ◽  
Author(s):  
Adeline Achard ◽  
Corinne Villers ◽  
Vianney Pichereau ◽  
Roland Leclercq

ABSTRACT Streptococcus agalactiae UCN36 was resistant to lincomycin (MIC = 16 μg/ml) but susceptible to clindamycin (MIC = 0.12 μg/ml) and erythromycin (MIC = 0.06 μg/ml). A 4-kb HindIII fragment was cloned from S. agalactiae UCN36 total DNA on plasmid pUC18 and introduced into Escherichia coli AG100A, where it conferred resistance to lincomycin. The sequence analysis of the fragment showed the presence of a 1,724-bp element delineated by imperfect inverted repeats (22 of 25 bp) and inserted in the operon for capsular synthesis of S. agalactiae UCN36. This element carried two open reading frames (ORF). The deduced amino acid sequence of the upstream ORF displayed similarity with transposases from anaerobes and IS1. The downstream ORF, lnu(C), encoded a 164-amino-acid protein with 26% to 27% identity with the LnuAN2, LnuA, and LnuA′ lincosamide nucleotidyltransferases reported for Bacteroides and Staphylococcus, respectively. Crude lysates of E. coli AG100A containing the cloned lnu(C) gene inactivated lincomycin and clindamycin in the presence of ATP and MgCl2. Mass spectrometry experiments demonstrated that the LnuC enzyme catalyzed adenylylation of lincomycin.

1998 ◽  
Vol 64 (5) ◽  
pp. 1650-1656 ◽  
Author(s):  
Peter W. Coschigano ◽  
Thomas S. Wehrman ◽  
L. Y. Young

ABSTRACT The denitrifying strain T1 is able to grow with toluene serving as its sole carbon source. Two mutants which have defects in this toluene utilization pathway have been characterized. A clone has been isolated, and subclones which contain tutD and tutE, two genes in the T1 toluene metabolic pathway, have been generated. ThetutD gene codes for an 864-amino-acid protein with a calculated molecular mass of 97,600 Da. The tutE gene codes for a 375-amino-acid protein with a calculated molecular mass of 41,300 Da. Two additional small open reading frames have been identified, but their role is not known. The TutE protein has homology to pyruvate formate-lyase activating enzymes. The TutD protein has homology to pyruvate formate-lyase enzymes, including a conserved cysteine residue at the active site and a conserved glycine residue that is activated to a free radical in this enzyme. Site-directed mutagenesis of these two conserved amino acids shows that they are also essential for the function of TutD.


1999 ◽  
Vol 341 (1) ◽  
pp. 51-59 ◽  
Author(s):  
Lu-Ping CHOW ◽  
Ning-Yuan SU ◽  
Chia-Jung YU ◽  
Bor-Luen CHIANG ◽  
Horng-Der SHEN

The mould genus, Penicillium, is known to be a significant source of environmental aero-allergens. One important allergen from Penicillium citrinum, Pen c 2, has been identified by means of two-dimensional immunoblotting using IgE-containing patients' sera. This novel allergen was cloned, sequenced and expressed in Escherichia coli. The cloned cDNA encodes a large 457-amino acid protein precursor containing a 16-amino acid signal peptide, a 120-amino acid propeptide and the 321-amino acid mature protein. Comparison of the Pen c 2 sequence with known protein sequences revealed shared high sequence similarities with two vacuolar serine proteases from Aspergillus niger and Saccharomyces cerevisiae. Asp-46, His-78 and Ser-244 were found to constitute the catalytic triad of the 39-kDa Pen c 2. The DNA coding for Pen c 2 was cloned into vector PQE-30 and expressed in E. coli as a His-tag fusion protein that bound serum IgE from Penicillium-allergic patients on immunoblots. Recombinant Pen c 2 could therefore be used effectively for diagnosis and also potentially for the treatment of mould-derived allergic disorders.


mBio ◽  
2016 ◽  
Vol 7 (6) ◽  
Author(s):  
Adi Oron-Gottesman ◽  
Martina Sauert ◽  
Isabella Moll ◽  
Hanna Engelberg-Kulka

ABSTRACT Escherichia coli mazEF is an extensively studied stress-induced toxin-antitoxin (TA) system. The toxin MazF is an endoribonuclease that cleaves RNAs at ACA sites. Thereby, under stress, the induced MazF generates a stress-induced translation machinery (STM), composed of MazF-processed mRNAs and selective ribosomes that specifically translate the processed mRNAs. Here, we further characterized the STM system, finding that MazF cleaves only ACA sites located in the open reading frames of processed mRNAs, while out-of-frame ACAs are resistant. This in-frame ACA cleavage of MazF seems to depend on MazF binding to an extracellular-death-factor (EDF)-like element in ribosomal protein bS1 (bacterial S1), apparently causing MazF to be part of STM ribosomes. Furthermore, due to the in-frame MazF cleavage of ACAs under stress, a bias occurs in the reading of the genetic code causing the amino acid threonine to be encoded only by its synonym codon ACC, ACU, or ACG, instead of by ACA. IMPORTANCE The genetic code is a universal characteristic of all living organisms. It defines the set of rules by which nucleotide triplets specify which amino acid will be incorporated into a protein. Our results represent the first existing report on a stress-induced bias in the reading of the genetic code. We found that in E. coli , under stress, the amino acid threonine is encoded only by its synonym codon ACC, ACU, or ACG, instead of by ACA. This is because under stress, MazF generates a stress-induced translation machinery (STM) in which MazF cleaves in-frame ACA sites of the processed mRNAs.


2004 ◽  
Vol 186 (9) ◽  
pp. 2862-2871 ◽  
Author(s):  
S. O'Flaherty ◽  
A. Coffey ◽  
R. Edwards ◽  
W. Meaney ◽  
G. F. Fitzgerald ◽  
...  

ABSTRACT Phage K is a polyvalent phage of the Myoviridae family which is active against a wide range of staphylococci. Phage genome sequencing revealed a linear DNA genome of 127,395 bp, which carries 118 putative open reading frames. The genome is organized in a modular form, encoding modules for lysis, structural proteins, DNA replication, and transcription. Interestingly, the structural module shows high homology to the structural module from Listeria phage A511, suggesting intergenus horizontal transfer. In addition, phage K exhibits the potential to encode proteins necessary for its own replisome, including DNA ligase, primase, helicase, polymerase, RNase H, and DNA binding proteins. Phage K has a complete absence of GATC sites, making it insensitive to restriction enzymes which cleave this sequence. Three introns (lys-I1, pol-I2, and pol-I3) encoding putative endonucleases were located in the genome. Two of these (pol-I2 and pol-I3) were found to interrupt the DNA polymerase gene, while the other (lys-I1) interrupts the lysin gene. Two of the introns encode putative proteins with homology to HNH endonucleases, whereas the other encodes a 270-amino-acid protein which contains two zinc fingers (CX2CX22CX2C and CX2CX23CX2C). The availability of the genome of this highly virulent phage, which is active against infective staphylococci, should provide new insights into the biology and evolution of large broad-spectrum polyvalent phages.


1998 ◽  
Vol 180 (17) ◽  
pp. 4753-4756 ◽  
Author(s):  
Francisco J. Pérez-Llarena ◽  
Antonio Rodríguez-García ◽  
Francisco J. Enguita ◽  
Juan F. Martín ◽  
Paloma Liras

ABSTRACT Three open reading frames (ORFs) have been located downstream ofcefE in the cephamycin C gene cluster of Streptomyces clavuligerus. ORF13 (pcd) encodes a 496-amino-acid protein (molecular weight [MW], 52,488) with an N-terminal amino acid sequence identical to that of pure piperideine-6-carboxylate dehydrogenase. ORF14 (cmcT) encodes a 523-amino-acid protein (MW, 54,232) analogous to Streptomyces proteins for efflux and resistance to antibiotics. ORF15 (pbp74) encodes a high molecular weight penicillin-binding protein (MW, 74,094).


2003 ◽  
Vol 185 (3) ◽  
pp. 714-725 ◽  
Author(s):  
Hédia Maamar ◽  
Pascale de Philip ◽  
Jean-Pierre Bélaich ◽  
Chantal Tardif

ABSTRACT Two new insertion sequences, ISCce1 and ISCce2, were found to be inserted into the cipC gene of spontaneous mutants of Clostridium cellulolyticum. In these insertional mutants, the cipC gene was disrupted either by ISCce1 alone or by both ISCce1 and ISCce2. ISCce1 is 1,292 bp long and has one open reading frame. The open reading frame encodes a putative 348-amino-acid protein with significant levels of identity with putative proteins having unknown functions and with some transposases belonging to the IS481 and IS3 families. Imperfect 23-bp inverted repeats were found near the extremities of ISCce1. ISCce2 is 1,359 bp long, carries one open reading frame, and has imperfect 35-bp inverted repeats at its termini. The open reading frame encodes a putative 398-amino-acid protein. This protein shows significant levels of identity with transposases belonging to the IS256 family. Upon transposition, both ISCce1 and ISCce2 generate 8-bp direct repeats of the target sequence, but no consensus sequences could be identified at either insertion site. ISCce1 is copied at least 20 times in the genome, as assessed by Southern blot analysis. ISCce2 was found to be mostly inserted into ISCce1. In addition, as neither of the elements was detected in seven other Clostridium species, we concluded that they may be specific to the C. cellulolyticum strain used.


2007 ◽  
Vol 52 (2) ◽  
pp. 626-630 ◽  
Author(s):  
Efthymia Petinaki ◽  
Véronique Guérin-Faublée ◽  
Vianney Pichereau ◽  
Corinne Villers ◽  
Adeline Achard ◽  
...  

ABSTRACT Streptococcus uberis UCN 42, isolated from a case of bovine mastitis, was intermediately resistant to lincomycin (MIC = 2 μg/ml) while remaining susceptible to clindamycin (MIC = 0.06 μg/ml) and erythromycin. A 1.1-kb SacI fragment was cloned from S. uberis UCN 42 total DNA on plasmid pUC 18 and introduced into Escherichia coli AG100A, where it conferred resistance to both clindamycin and lincomycin. The sequence analysis of the fragment showed the presence of a new gene, named lnu(D), that encoded a 164-amino-acid protein with 53% identity with Lnu(C) previously reported to occur in Streptococcus agalactiae. Crude lysates of E. coli AG100A containing the cloned lnu(D) gene inactivated lincomycin and clindamycin in the presence of ATP and MgCl2. Mass spectrometry experiments demonstrated that the lnu(D) enzyme catalyzed adenylylation of clindamycin. A domain conserved in deduced sequences of lincosamide O-nucleotidyltransferases Lnu(A), Lnu(C), LinAN2, and Lin(D) and in the aminoglycoside nucleotidyltransferase ANT(2′′) was identified.


2000 ◽  
Vol 66 (7) ◽  
pp. 2965-2971 ◽  
Author(s):  
John K. Davis ◽  
George C. Paoli ◽  
Zhongqi He ◽  
Lloyd J. Nadeau ◽  
Charles C. Somerville ◽  
...  

ABSTRACT Pseudomonas pseudoalcaligenes JS45 grows on nitrobenzene by a partially reductive pathway in which the intermediate hydroxylaminobenzene is enzymatically rearranged to 2-aminophenol by hydroxylaminobenzene mutase (HAB mutase). The properties of the enzyme, the reaction mechanism, and the evolutionary origin of the gene(s) encoding the enzyme are unknown. In this study, two open reading frames (habA and habB), each encoding an HAB mutase enzyme, were cloned from a P. pseudoalcaligenes JS45 genomic library and sequenced. The open reading frames encoding HabA and HabB are separated by 2.5 kb and are divergently transcribed. The deduced amino acid sequences of HabA and HabB are 44% identical. The HAB mutase specific activities in crude extracts of Escherichia coli clones synthesizing either HabA or HabB were similar to the specific activities of extracts of strain JS45 grown on nitrobenzene. HAB mutase activity in E. coli extracts containing HabB withstood heating at 85�C for 10 min, but extracts containing HabA were inactivated when they were heated at temperatures above 60�C. HAB mutase activity in extracts of P. pseudoalcaligenesJS45 grown on nitrobenzene exhibited intermediate temperature stability. Although both the habA gene and thehabB gene conferred HAB mutase activity when they were separately cloned and expressed in E. coli, reverse transcriptase PCR analysis indicated that only habA is transcribed in P. pseudoalcaligenes JS45. A mutant strain derived from strain JS45 in which the habA gene was disrupted was unable to grow on nitrobenzene, which provided physiological evidence that HabA is involved in the degradation of nitrobenzene. A strain in which habB was disrupted grew on nitrobenzene. Gene Rv3078 of Mycobacterium tuberculosisH37Rv encodes a protein whose deduced amino acid sequence is 52% identical to the HabB amino acid sequence. E. colicontaining M. tuberculosis gene Rv3078 cloned into pUC18 exhibited low levels of HAB mutase activity. Sequences that exhibit similarity to transposable element sequences are present between habA and habB, as well as downstream ofhabB, which suggests that horizontal gene transfer resulted in acquisition of one or both of the hab genes.


Genetics ◽  
2001 ◽  
Vol 159 (3) ◽  
pp. 1103-1115 ◽  
Author(s):  
Hongguang Shao ◽  
Zhijian Tu

Abstract A novel transposon named ITmD37E was discovered in a wide range of mosquito species. Sequence analysis of multiple copies in three Aedes species showed similar terminal inverted repeats and common putative TA target site duplications. The ITmD37E transposases contain a conserved DD37E catalytic motif, which is unique among reported transposons of the IS630-Tc1-mariner superfamily. Sequence comparisons and phylogenetic analyses suggest that ITmD37E forms a novel family distinct from the widely distributed Tc1 (DD34E), mariner (DD34D), and pogo (DDxD) families in the IS630-Tc1-mariner superfamily. The inclusion in the phylogenetic analysis of recently reported transposons and transposons uncovered in our database survey provided revisions to previous classifications and identified two additional families, ITmD37D and ITmD39D, which contain DD37D and DD39D motifs, respectively. The above expansion and reorganization may open the doors to the discovery of related transposons in a broad range of organisms and help illustrate the evolution and structure-function relationships among these distinct transposases in the IS630-Tc1-mariner superfamily. The presence of intact open reading frames and highly similar copies in some of the newly characterized transposons suggests recent transposition. Studies of these novel families may add to the limited repertoire of transgenesis and mutagenesis tools for a wide range of organisms, including the medically important mosquitoes.


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