scholarly journals Molecular Characterization of Chromosomal Class C β-Lactamase and Its Regulatory Gene in Ochrobactrum anthropi

2001 ◽  
Vol 45 (8) ◽  
pp. 2324-2330 ◽  
Author(s):  
David Nadjar ◽  
Roger Labia ◽  
Claude Cerceau ◽  
Chantal Bizet ◽  
Alain Philippon ◽  
...  
Keyword(s):  
Amino Acid ◽  
Regulatory Gene ◽  
Amino Acid Sequences ◽  
Clinical Strain ◽  
Kinetic Properties ◽  
Ochrobactrum Anthropi ◽  
Amino Terminal ◽  
Class C ◽  
Human Infections ◽  
Reference Strains

ABSTRACT Ochrobactrum anthropi, formerly known as CDC group Vd, is an oxidase-producing, gram-negative, obligately aerobic, non-lactose-fermenting bacillus of low virulence that occasionally causes human infections. It is highly resistant to all β-lactams except imipenem. A clinical isolate, SLO74, and six reference strains were tested. MICs of penicillins, aztreonam, and most cephalosporins tested, including cefotaxime and ceftazidime, were >128 μg/ml and of cefepime were 64 to >128 μg/ml. Clavulanic acid was ineffective and tazobactam had a weak effect in association with piperacillin. Two genes, ampR and ampC, were cloned by inserting restriction fragments of genomic DNA from the clinical strain O. anthropi SLO74 into pBK-CMV to give the recombinant plasmid pBK-OA1. The pattern of resistance to β-lactams of this clone was similar to that of the parental strain, except for its resistance to cefepime (MIC, 0.5 μg/ml). The deduced amino acid sequence of the AmpC β-lactamase (pI, 8.9) was only 41 to 52% identical to the sequence of other chromosomally encoded and plasmid-encoded class C β-lactamases. The kinetic properties of this β-lactamase were typical for this class of β-lactamases. Upstream from the ampC gene, the ampR gene encodes a protein with a sequence that is 46 to 62% identical to those of other AmpR proteins and with an amino-terminal DNA-binding domain typical of transcriptional activators of the Lys-R family. The deduced amino acid sequences of theampC genes of the six reference strains were 96 to 99% identical to the sequence of the clinical strain. The β-lactamase characterized from strain SLO74 was named OCH-1 (gene, bla OCH-I).

scholarly journals Novel Plasmid-Encoded Class C β-Lactamase (MOX-2) in Klebsiella pneumoniae from Greece

2002 ◽  
Vol 46 (7) ◽  
pp. 2262-2265 ◽  
Author(s):  
Laurent Raskine ◽  
Isabelle Borrel ◽  
Guilène Barnaud ◽  
Sophie Boyer ◽  
Béatrice Hanau-Berçot ◽  
...  
Keyword(s):  
Amino Acid ◽  
Klebsiella Pneumoniae ◽  
Hydrolytic Activity ◽  
Amino Acid Sequences ◽  
Clinical Strain ◽  
Aeromonas Sobria ◽  
Class C

ABSTRACT Klebsiella pneumoniae KOL, a clinical strain resistant to various β-lactams, was isolated from the stools of a patient from Greece. This strain harbored a new pI 9.1 plasmid-mediated AmpC β-lactamase with unusually high levels of hydrolytic activity for cefoxitin and cefotetan that we named MOX-2. Sequencing of bla MOX-2 revealed 93.2, 92.9, 92.7, and 73.1% identities with the deduced amino acid sequences of CMY-8, MOX-1, CMY-1, and the AmpC β-lactamase of Aeromonas sobria, respectively.

Diversity of Primary Structures of the Carboxy-terminal Regions of Mammalian Fibrinogen Aα-Chains

1993 ◽  
Vol 69 (04) ◽  
pp. 351-360 ◽  
Author(s):  
Masahiro Murakawa ◽  
Takashi Okamura ◽  
Takumi Kamura ◽  
Tsunefumi Shibuya ◽  
Mine Harada ◽  
...  
Keyword(s):  
Amino Acid ◽  
Rhesus Monkey ◽  
Syrian Hamster ◽  
Tandem Repeats ◽  
Mammalian Species ◽  
Amino Acid Sequences ◽  
Point Of View ◽  
Cross Linking ◽  
Amino Terminal ◽  
Rgd Sequence

SummaryThe partial amino acid sequences of fibrinogen Aα-chains from five mammalian species have been inferred by means of the polymerase chain reaction (PCR). From the genomic DNA of the rhesus monkey, pig, dog, mouse and Syrian hamster, the DNA fragments coding for α-C domains in the Aα-chains were amplified and sequenced. In all species examined, four cysteine residues were always conserved at the homologous positions. The carboxy- and amino-terminal portions of the α-C domains showed a considerable homology among the species. However, the sizes of the middle portions, which corresponded to the internal repeat structures, showed an apparent variability because of several insertions and/or deletions. In the rhesus monkey, pig, mouse and Syrian hamster, 13 amino acid tandem repeats fundamentally similar to those in humans and the rat were identified. In the dog, however, tandem repeats were found to consist of 18 amino acids, suggesting an independent multiplication of the canine repeats. The sites of the α-chain cross-linking acceptor and α2-plasmin inhibitor cross-linking donor were not always evolutionally conserved. The arginyl-glycyl-aspartic acid (RGD) sequence was not found in the amplified region of either the rhesus monkey or the pig. In the canine α-C domain, two RGD sequences were identified at the homologous positions to both rat and human RGD S. In the Syrian hamster, a single RGD sequence was found at the same position to that of the rat. Triplication of the RGD sequences was seen in the murine fibrinogen α-C domain around the homologous site to the rat RGDS sequence. These findings are of some interest from the point of view of structure-function and evolutionary relationships in the mammalian fibrinogen Aα-chains.

scholarly journals Cloning and Characterization of a Chromosomal Class C β-Lactamase and Its Regulatory Gene in Laribacter hongkongensis

2005 ◽  
Vol 49 (5) ◽  
pp. 1957-1964 ◽  
Author(s):  
Susanna K. P. Lau ◽  
Pak-leung Ho ◽  
Maria W. S. Li ◽  
Hoi-wah Tsoi ◽  
Raymond W. H. Yung ◽  
...  
Keyword(s):  
Genomic Dna ◽  
Southern Hybridization ◽  
Regulatory Gene ◽  
Kinetic Properties ◽  
Restriction Fragments ◽  
Regulatory Systems ◽  
Laribacter Hongkongensis ◽  
Consensus Motifs ◽  
Class C

ABSTRACT Laribacter hongkongensis, a newly discovered bacterium recently shown to be associated with community-acquired gastroenteritis, is generally resistant to most β-lactams except the carbapenems. We describe the cloning and characterization of a novel chromosomal class C β-lactamase and its regulatory gene in L. hongkongensis. Two genes, ampC and ampR, were cloned by inserting restriction fragments of genomic DNA from L. hongkongensis strain HLHK5 into pBK-CMV to give the recombinant plasmid pBK-LHK-5. The ampR and ampC genes and their promoters were divergently oriented, with the ampR gene immediately upstream of the ampC gene and an intercistronic Lys-R motif, typical of inducible ampC-ampR regulatory systems. The deduced amino acid sequence of the cloned AmpC β-lactamase (pI 8.1) contained consensus motifs characteristic of class C β-lactamases but had identities no greater than 46% to known class C β-lactamases. The kinetic properties of this AmpC were also compatible with those of a class C β-lactamase. PCR of 20 clinical isolates of L. hongkongensis, including HLHK5, showed the presence of both ampC and ampR genes in all isolates. Southern hybridization suggested that the ampC gene of HLHK5 was chromosomally encoded. Subcloning experiments showed that the expression of the ampC gene of HLHK5 was regulated by its ampR gene, which acts as a repressor. The β-lactamase characterized from strain HLHK5 was named LHK-5 (gene, bla LHK-5) and represents the first example of AmpC β-lactamase in the β subdivision of proteobacteria.

Neisseria pili proteins: amino-terminal amino acid sequences and identification of an unusual amino acid

Biochemistry ◽  
1978 ◽  
Vol 17 (3) ◽  
pp. 442-445 ◽  
Author(s):  
Mark A. Hermodson ◽  
Kirk C. S. Chen ◽  
Thomas M. Buchanan
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequences ◽  
Terminal Amino Acid ◽  
Amino Terminal ◽  
Terminal Amino ◽  
Unusual Amino Acid

scholarly journals Novel Bifunctional α-l-Arabinofuranosidase/Xylobiohydrolase (ABF3) from Penicillium purpurogenum

2010 ◽  
Vol 76 (15) ◽  
pp. 5247-5253 ◽  
Author(s):  
Mar�a Cristina Ravanal ◽  
Eduardo Callegari ◽  
Jaime Eyzaguirre
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Glycosyl Hydrolase ◽  
Biochemical Properties ◽  
Amino Acid Sequences ◽  
Mass Spectrometry Analysis ◽  
Carbohydrate Binding ◽  
Penicillium Purpurogenum ◽  
Spectrometry Analysis ◽  
Amino Terminal

ABSTRACT The soft rot fungus Penicillium purpurogenum grows on a variety of natural substrates and secretes various isoforms of xylanolytic enzymes, including three arabinofuranosidases. This work describes the biochemical properties as well as the nucleotide and amino acid sequences of arabinofuranosidase 3 (ABF3). This enzyme has been purified to homogeneity. It is a glycosylated monomer with a molecular weight of 50,700 and can bind cellulose. The enzyme is active with p-nitrophenyl α-l-arabinofuranoside and p-nitrophenyl β-d-xylopyranoside with a Km of 0.65 mM and 12 mM, respectively. The enzyme is active on xylooligosaccharides, yielding products of shorter length, including xylose. However, it does not hydrolyze arabinooligosaccharides. When assayed with polymeric substrates, little arabinose is liberated from arabinan and debranched arabinan; however, it hydrolyzes arabinose and releases xylooligosaccharides from arabinoxylan. Sequencing both ABF3 cDNA and genomic DNA reveals that this gene does not contain introns and that the open reading frame is 1,380 nucleotides in length. The deduced mature protein is composed of 433 amino acids residues and has a calculated molecular weight of 47,305. The deduced amino acid sequence has been validated by mass spectrometry analysis of peptides from purified ABF3. A total of 482 bp of the promoter were sequenced; putative binding sites for transcription factors such as CreA (four), XlnR (one), and AreA (three) and two CCAAT boxes were found. The enzyme has two domains, one similar to proteins of glycosyl hydrolase family 43 at the amino-terminal end and a family 6 carbohydrate binding module at the carboxyl end. ABF3 is the first described modular family 43 enzyme from a fungal source, having both α-l-arabinofuranosidase and xylobiohydrolase functionalities.

Comparison of the structural and kinetic properties of the cytochrome c nitrite reductases from Escherichia coli, Wolinella succinogenes, Sulfurospirillum deleyianum and Desulfovibrio desulfuricans

2006 ◽  
Vol 34 (1) ◽  
pp. 143-145 ◽  
Author(s):  
T.A. Clarke ◽  
A.M. Hemmings ◽  
B. Burlat ◽  
J.N. Butt ◽  
J.A. Cole ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Active Site ◽  
Desulfovibrio Desulfuricans ◽  
Amino Acid Sequences ◽  
Kinetic Properties ◽  
Wolinella Succinogenes ◽  
Nitrite Reductases ◽  
Sulphite Reductase

The recent crystallographic characterization of NrfAs from Sulfurospirillum deleyianum, Wolinella succinogenes, Escherichia coli and Desulfovibrio desulfuricans allows structurally conserved regions to be identified. Comparison of nitrite and sulphite reductase activities from different bacteria shows that the relative activities vary according to organism. By comparison of both amino acid sequences and structures, differences can be identified in the monomer–monomer interface and the active-site channel; these differences could be responsible for the observed variance in substrate activity and indicate that subtle changes in the NrfA structure may optimize the enzyme for different roles.

scholarly journals IgA proteases of two distinct specificities are released by Neisseria meningitidis.

1980 ◽  
Vol 152 (5) ◽  
pp. 1442-1447 ◽  
Author(s):  
M H Mulks ◽  
A G Plaut ◽  
H A Feldman ◽  
B Frangione
Keyword(s):  
Amino Acid ◽  
Neisseria Meningitidis ◽  
Heavy Chain ◽  
Peptide Bond ◽  
Amino Acid Sequences ◽  
Hinge Region ◽  
Amino Terminal ◽  
Group A

Strains of Neisseria meningitidis produce two distinct extracellular IgA proteases that cleave the human IgA1 heavy chain at different points within the hinge region. Type 1 protease cleaves the prolyl-seryl peptide bond at position 237-238; type type 2 protease cleaves the prolyl-threonyl bond two residues amino terminal to that bond attacked by type 1 enzyme. Each meningococcal isolate elaborates only one of these two enzymes, and the type of protease produced correlates with certain serogroups: group A yielding only type 1, and groups X and Y only type 2 enzyme. In addition, analysis of amino acid sequences of human alpha-chain proteins reveals that the repeating octapeptide characteristic of the IgA1 hinge region is actually triplicated.

scholarly journals nit-4, a pathway-specific regulatory gene of Neurospora crassa, encodes a protein with a putative binuclear zinc DNA-binding domain.

1991 ◽  
Vol 11 (11) ◽  
pp. 5735-5745 ◽  
Author(s):  
G F Yuan ◽  
Y H Fu ◽  
G A Marzluf
Keyword(s):  
Amino Acid ◽  
Dna Binding ◽  
Neurospora Crassa ◽  
Transcriptional Activation ◽  
Regulatory Gene ◽  
Binding Domain ◽  
Site Directed Mutagenesis ◽  
Dna Binding Domain ◽  
Amino Terminal ◽  
Rich Domain

nit-4, a pathway-specific regulatory gene in the nitrogen circuit of Neurospora crassa, is required for the expression of nit-3 and nit-6, the structural genes which encode nitrate and nitrite reductase, respectively. The complete nucleotide sequence of the nit-4 gene has been determined. The predicted NIT4 protein contains 1,090 amino acids and appears to possess a single Zn(II)2Cys6 binuclear-type zinc finger, which may mediate DNA binding. Site-directed mutagenesis studies demonstrated that cysteine and other conserved amino acid residues in this possible DNA-binding domain are necessary for nit-4 function. A stretch of 27 glutamines, encoded by a CAGCAA repeating sequence, occurs in the C terminus of the NIT4 protein, and a second glutamine-rich domain occurs further upstream. A NIT4 protein deleted for the polyglutamine region was still functional in vivo. However, nit-4 function was abolished when both the polyglutamine region and the glutamine-rich domain were deleted, suggesting that the glutamine-rich domain might function in transcriptional activation. The homologous regulatory gene from Aspergillus nidulans, nirA, encodes a protein whose amino-terminal half has approximately 60% amino acid identity with NIT4 but whose carboxy terminus is completely different. A hybrid nit-4-nirA gene was constructed and found to function in N. crassa.

scholarly journals Haemoglobins of the Shark, Heterodontus Portusjacksoni II. Amino Acid Sequence of the a-Chain

1976 ◽  
Vol 29 (2) ◽  
pp. 73 ◽  
Author(s):  
AR Nash ◽  
WK Fisher ◽  
EOP Thompson
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Paper Chromatography ◽  
Cyanogen Bromide ◽  
Gel Filtration ◽  
Amino Acid Sequences ◽  
Tryptic Digestion ◽  
Amino Terminal ◽  
Core Peptide ◽  
A Chain

The amino acid sequence of the a-chain of the principal haemoglobin from the shark, H. portusjacksoni has been determined. The chain has 148 residues and is acetylated at the amino terminal. The soluble peptides obtained by tryptic and chymotryptic digestion of the protein or its cyanogen bromide fragments were isolated by gel filtration, paper ionophoresis and paper chromatography. The amino acid sequences were determined by the dansyl-Edman procedure. The insoluble 'core' peptide from the tryptic digestion contained 34 residues and required cleavage by several proteases before the sequence was established. Compared with human a-chain there are 88 amino acid differences including the additional seven residues which appear on the amino terminal of the shark chain. There is also one deletion and one insertion. The chain contains no tryptophan but has four cysteinyl residues which is the highest number of such residues recorded for a vertebrate globin.

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