scholarly journals A Novel Extended-Spectrum β-Lactamase, SGM-1, from an Environmental Isolate of Sphingobium sp.

2013 ◽  
Vol 57 (8) ◽  
pp. 3783-3788 ◽  
Author(s):  
Toni L. Lamoureaux ◽  
Viktoria Vakulenko ◽  
Marta Toth ◽  
Hilary Frase ◽  
Sergei B. Vakulenko
Keyword(s):  
Amino Acid ◽  
Clavulanic Acid ◽  
Amino Acid Sequence Identity ◽  
Susceptibility Testing ◽  
Environmental Isolate ◽  
Significant Activity ◽  
Content Type ◽  
Sequence Identity ◽  
Class A ◽  
Extended Spectrum

ABSTRACTSGM-1 is a novel class A β-lactamase from an environmental isolate ofSphingobiumsp. containing all of the distinct amino acid motifs of class A β-lactamases. It shares 77 to 80% amino acid sequence identity with putative β-lactamases that are present on the chromosome of allSphingobiumspecies whose genomes were sequenced and annotated. Thus, SGM-type β-lactamases are native to this genus. Antibiotic susceptibility testing classifies SGM-1 as an extended-spectrum β-lactamase, conferring the highest level of resistance to penicillins. Although SGM-1 contains the conserved cysteine residues characteristic of class A carbapenemases, it does not confer resistance to the carbapenem antibiotics imipenem, meropenem, or doripenem but does increase the MIC of ertapenem 8-fold. SGM-1 hydrolyzes penicillins and the monobactam aztreonam with similar catalytic efficiencies, ranging from 105to 106M−1s−1. The catalytic efficiencies of SGM-1 for cefoxitin and ceftazidime were the lowest (102to 103M−1s−1) among the cephalosporins tested, while the catalytic efficiencies against all other cephalosporins varied from about 105to 106M−1s−1. SGM-1 exhibited measurable but not significant activity toward the carbapenems tested. SGM-1 also showed high affinity for clavulanic acid, tazobactam, and sulbactam (Ki< 1 μM); however, only clavulanic acid significantly reduced the MICs of β-lactams.

scholarly journals Class A Carbapenemase FPH-1 from Francisella philomiragia

2012 ◽  
Vol 56 (6) ◽  
pp. 2852-2857 ◽  
Author(s):  
Marta Toth ◽  
Viktoria Vakulenko ◽  
Nuno T. Antunes ◽  
Hilary Frase ◽  
Sergei B. Vakulenko
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Sequence Identity ◽  
Content Type ◽  
E Coli ◽  
New Class ◽  
Sequence Identity ◽  
Class A ◽  
High Level ◽  
Level Resistance

ABSTRACTFPH-1 is a new class A carbapenemase fromFrancisella philomiragia. It produces high-level resistance to penicillins and the narrow-spectrum cephalosporin cephalothin and hydrolyzes these β-lactam antibiotics with catalytic efficiencies of 106to 107M−1s−1. When expressed inEscherichia coli, the enzyme confers resistance to clavulanic acid, tazobactam, and sulbactam and hasKivalues of 7.5, 4, and 220 μM, respectively, against these inhibitors. FPH-1 increases the MIC of the monobactam aztreonam 256-fold and the MIC of the broad-spectrum cephalosporin ceftazidime 128-fold, while the MIC of cefoxitin remains unchanged. MICs of the carbapenem antibiotics imipenem, meropenem, doripenem, and ertapenem are elevated 8-, 8-, 16-, and 64-fold, respectively, against anE. coliJM83 strain producing the FPH-1 carbapenemase. The catalytic efficiencies of the enzyme against carbapenems are in the range of 104to 105M−1s−1. FPH-1 is 77% identical to the FTU-1 β-lactamase fromFrancisella tularensisand has low amino acid sequence identity with other class A β-lactamases. Together with FTU-1, FPH-1 constitutes a new branch of the prolific and ever-expanding class A β-lactamase tree.

scholarly journals The Class A β-Lactamase FTU-1 Is Native to Francisella tularensis

2011 ◽  
Vol 56 (2) ◽  
pp. 666-671 ◽  
Author(s):  
Nuno T. Antunes ◽  
Hilary Frase ◽  
Marta Toth ◽  
Sergei B. Vakulenko
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Francisella Tularensis ◽  
Amino Acid Sequence Identity ◽  
Cysteine Residues ◽  
Content Type ◽  
Sequence Identity ◽  
Class A

ABSTRACTThe class A β-lactamase FTU-1 produces resistance to penicillins and ceftazidime but not to any other β-lactam antibiotics tested. FTU-1 hydrolyzes penicillin antibiotics with catalytic efficiencies of 105to 106M−1s−1and cephalosporins and carbapenems with catalytic efficiencies of 102to 103M−1s−1, but the monobactam aztreonam and the cephamycin cefoxitin are not substrates for the enzyme. FTU-1 shares 21 to 34% amino acid sequence identity with other class A β-lactamases and harbors two cysteine residues conserved in all class A carbapenemases. FTU-1 is the first weak class A carbapenemase that is native toFrancisella tularensis.

scholarly journals Distinct Regioselectivity of Fungal P450 Enzymes for Steroidal Hydroxylation

2019 ◽  
Vol 85 (18) ◽  
Author(s):  
Wei Lu ◽  
Jinhui Feng ◽  
Xi Chen ◽  
Yun-Juan Bao ◽  
Yu Wang ◽  
...  
Keyword(s):  
Amino Acid ◽  
Pichia Pastoris ◽  
Organic Synthesis ◽  
Transcriptome Sequencing ◽  
Amino Acid Sequence Identity ◽  
Steroid Nucleus ◽  
Content Type ◽  
Whole Cells ◽  
Sequence Identity ◽  
High Amino Acid

ABSTRACT In this study, we identified two P450 enzymes (CYP5150AP3 and CYP5150AN1) from Thanatephorus cucumeris NBRC 6298 by combination of transcriptome sequencing and heterologous expression in Pichia pastoris. The biotransformation of 11-deoxycortisol and testosterone by Pichia pastoris whole cells coexpressing the cyp5150ap3 and por genes demonstrated that the CYP5150AP3 enzyme possessed steroidal 7β-hydroxylase activities toward these substrates, and the regioselectivity was dependent on the structures of steroidal compounds. CYP5150AN1 catalyzed the 2β-hydroxylation of 11-deoxycortisol. It is interesting that they display different regioselectivity of hydroxylation from that of their isoenzyme, CYP5150AP2, which possesses 19- and 11β-hydroxylase activities. IMPORTANCE The steroidal hydroxylases CYP5150AP3 and CYP5150AN1 together with the previously characterized CYP5150AP2 belong to the CYP5150A family of P450 enzymes with high amino acid sequence identity, but they showed completely different regioselectivities toward 11-deoxycortisol, suggesting the regioselectivity diversity of steroidal hydroxylases of CYP5150 family. They are also distinct from the known bacterial and fungal steroidal hydroxylases in substrate specificity and regioselectivity. Biocatalytic hydroxylation is one of the important transformations for the functionalization of steroid nucleus rings but remains a very challenging task in organic synthesis. These hydroxylases are useful additions to the toolbox of hydroxylase enzymes for the functionalization of steroids at various positions.

scholarly journals Substitutions at Position 105 in SHV Family β-Lactamases Decrease Catalytic Efficiency and Cause Inhibitor Resistance

2012 ◽  
Vol 56 (11) ◽  
pp. 5678-5686 ◽  
Author(s):  
Mei Li ◽  
Benjamin C. Conklin ◽  
Magdalena A. Taracila ◽  
Rebecca A. Hutton ◽  
Marion J. Skalweit
Keyword(s):  
Clavulanic Acid ◽  
Susceptibility Testing ◽  
Catalytic Efficiency ◽  
Wild Type ◽  
Oxyanion Hole ◽  
Content Type ◽  
Class A ◽  
Inhibitor Resistance ◽  
Structural Probes ◽  
Variant Residue

ABSTRACTAmbler position 105 in class A β-lactamases is implicated in resistance to clavulanic acid, although no clinical isolates with mutations at this site have been reported. We hypothesized that Y105 is important in resistance to clavulanic acid because changes in positioning of the inhibitor for ring oxygen protonation could occur. In addition, resistance to bicyclic 6-methylidene penems, which are interesting structural probes that inhibit all classes of serine β-lactamases with nanomolar affinity, might emerge with substitutions at position 105, especially with nonaromatic substitutions. All 19 variants of SHV-1 with variations at position 105 were prepared. Antimicrobial susceptibility testing showed thatEscherichia coliDH10B expressing Y105 variants retained activity against ampicillin, except for the Y105L variant, which was susceptible to all β-lactams, similar to the case for the host control strain. Several variants had elevated MICs to ampicillin-clavulanate. However, all the variants remained susceptible to piperacillin in combination with a penem inhibitor (MIC, ≤2/4 mg/liter). The Y105E, -F, -M, and -R variants demonstrated reduced catalytic efficiency toward ampicillin compared to the wild-type (WT) enzyme, which was caused by increasedKm. Clavulanic acid and penemKivalues were also increased for some of the variants, especially Y105E. Mutagenesis at position 105 in SHV yields mutants resistant to clavulanate with reduced catalytic efficiency for ampicillin and nitrocefin, similar to the case for the class A carbapenemase KPC-2. Our modeling analyses suggest that resistance is due to oxyanion hole distortion. Susceptibility to a penem inhibitor is retained although affinity is decreased, especially for the Y105E variant. Residue 105 is important to consider when designing new inhibitors.

scholarly journals Genetic and Biochemical Characterization of OXA-535, a Distantly Related OXA-48-Like β-Lactamase

2018 ◽  
Vol 62 (10) ◽  
Author(s):  
L. Dabos ◽  
A. B. Jousset ◽  
R. A. Bonnin ◽  
N. Fortineau ◽  
A. Zavala ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Amino Acid Sequence Identity ◽  
Biochemical Characterization ◽  
Content Type ◽  
Sequence Identity

ABSTRACT OXA-535 is a chromosome-encoded carbapenemase of Shewanella bicestrii JAB-1 that shares only 91.3% amino acid sequence identity with OXA-48. Catalytic efficiencies are similar to those of OXA-48 for most β-lactams, except for ertapenem, where a 2,000-fold-higher efficiency was observed with OXA-535. OXA-535 and OXA-436, a plasmid-encoded variant of OXA-535 differing by three amino acids, form a novel cluster of distantly related OXA-48-like carbapenemases. Comparison of blaOXA-535 and blaOXA-436 genetic environments suggests that an ISCR1 may be responsible for blaOXA-436 gene mobilization from the chromosome of Shewanella spp. to plasmids.

scholarly journals Chromosome-Encoded Broad-Spectrum Ambler Class A β-Lactamase RUB-1 from Serratia rubidaea

2016 ◽  
Vol 61 (2) ◽  
Author(s):  
Rémy A. Bonnin ◽  
Jennifer Didi ◽  
Ayla Ergani ◽  
Sandra Lima ◽  
Thierry Naas
Keyword(s):  
Amino Acid Sequence Identity ◽  
Consensus Sequence ◽  
Whole Genome ◽  
Content Type ◽  
Promoter Sequences ◽  
Sequence Identity ◽  
Class A ◽  
Rapid Amplification ◽  
Lactamase Gene ◽  
Serratia Rubidaea

ABSTRACT Whole-genome sequencing of Serratia rubidaea CIP 103234T revealed a chromosomally located Ambler class A β-lactamase gene. The gene was cloned, and the β-lactamase, RUB-1, was characterized. RUB-1 displayed 74% and 73% amino acid sequence identity with the GIL-1 and TEM-1 penicillinases, respectively, and its substrate profile was similar to that of the latter β-lactamases. Analysis by 5′ rapid amplification of cDNA ends revealed promoter sequences highly divergent from the Escherichia coli σ70 consensus sequence. This work further illustrates the heterogeneity of β-lactamases among Serratia spp.

scholarly journals Comparative Biochemical and Structural Analysis of Novel Cellulose Binding Proteins (Tāpirins) from Extremely Thermophilic Caldicellulosiruptor Species

2018 ◽  
Vol 85 (3) ◽  
Author(s):  
Laura L. Lee ◽  
William S. Hart ◽  
Vladimir V. Lunin ◽  
Markus Alahuhta ◽  
Yannick J. Bomble ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Microcrystalline Cellulose ◽  
Binding Proteins ◽  
Amino Acid Sequence Identity ◽  
Plant Biomass ◽  
Three Dimensional ◽  
Content Type ◽  
Sequence Identity ◽  
Cellulose Binding

ABSTRACT Genomes of extremely thermophilic Caldicellulosiruptor species encode novel cellulose binding proteins, called tāpirins, located proximate to the type IV pilus locus. The C-terminal domain of Caldicellulosiruptor kronotskyensis tāpirin 0844 (Calkro_0844) is structurally unique and has a cellulose binding affinity akin to that seen with family 3 carbohydrate binding modules (CBM3s). Here, full-length and C-terminal versions of tāpirins from Caldicellulosiruptor bescii (Athe_1870), Caldicellulosiruptor hydrothermalis (Calhy_0908), Caldicellulosiruptor kristjanssonii (Calkr_0826), and Caldicellulosiruptor naganoensis (NA10_0869) were produced recombinantly in Escherichia coli and compared to Calkro_0844. All five tāpirins bound to microcrystalline cellulose, switchgrass, poplar, and filter paper but not to xylan. Densitometry analysis of bound protein fractions visualized by SDS-PAGE revealed that Calhy_0908 and Calkr_0826 (from weakly cellulolytic species) associated with the cellulose substrates to a greater extent than Athe_1870, Calkro_0844, and NA10_0869 (from strongly cellulolytic species). Perhaps this relates to their specific needs to capture glucans released from lignocellulose by cellulases produced in Caldicellulosiruptor communities. Calkro_0844 and NA10_0869 share a higher degree of amino acid sequence identity (>80% identity) with each other than either does with Athe_1870 (∼50%). The levels of amino acid sequence identity of Calhy_0908 and Calkr_0826 to Calkro_0844 were only 16% and 36%, respectively, although the three-dimensional structures of their C-terminal binding regions were closely related. Unlike the parent strain, C. bescii mutants lacking the tāpirin genes did not bind to cellulose following short-term incubation, suggesting a role in cell association with plant biomass. Given the scarcity of carbohydrates in neutral terrestrial hot springs, tāpirins likely help scavenge carbohydrates from lignocellulose to support growth and survival of Caldicellulosiruptor species. IMPORTANCE The mechanisms by which microorganisms attach to and degrade lignocellulose are important to understand if effective approaches for conversion of plant biomass into fuels and chemicals are to be developed. Caldicellulosiruptor species grow on carbohydrates from lignocellulose at elevated temperatures and have biotechnological significance for that reason. Novel cellulose binding proteins, called tāpirins, are involved in the way that Caldicellulosiruptor species interact with microcrystalline cellulose, and additional information about the diversity of these proteins across the genus, including binding affinity and three-dimensional structural comparisons, is provided here.

scholarly journals Molecular Mechanism of Nicotine Degradation by a Newly Isolated Strain, Ochrobactrum sp. Strain SJY1

2014 ◽  
Vol 81 (1) ◽  
pp. 272-281 ◽  
Author(s):  
Hao Yu ◽  
Hongzhi Tang ◽  
Xiongyu Zhu ◽  
Yangyang Li ◽  
Ping Xu
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Amino Acid Sequence Identity ◽  
Specific Activity ◽  
Amine Oxidase ◽  
Sole Source ◽  
Content Type ◽  
Sequence Identity ◽  
Nicotine Degradation ◽  
Functional Pathway

ABSTRACTA newly isolated strain, SJY1, identified asOchrobactrumsp., utilizes nicotine as a sole source of carbon, nitrogen, and energy. Strain SJY1 could efficiently degrade nicotine via a variant of the pyridine and pyrrolidine pathways (the VPP pathway), which highlights bacterial metabolic diversity in relation to nicotine degradation. A 97-kbp DNA fragment containing six nicotine degradation-related genes was obtained by gap closing from the genome sequence of strain SJY1. Three genes, designatedvppB,vppD, andvppE, in the VPP pathway were cloned and heterologously expressed, and the related proteins were characterized. ThevppBgene encodes a flavin-containing amine oxidase converting 6-hydroxynicotine to 6-hydroxy-N-methylmyosmine. Although VppB specifically catalyzes the dehydrogenation of 6-hydroxynicotine rather than nicotine, it shares higher amino acid sequence identity with nicotine oxidase (38%) from the pyrrolidine pathway than with its isoenzyme (6-hydroxy-l-nicotine oxidase, 24%) from the pyridine pathway. ThevppDgene encodes an NADH-dependent flavin-containing monooxygenase, which catalyzes the hydroxylation of 6-hydroxy-3-succinoylpyridine to 2,5-dihydroxypyridine. VppD shows 62% amino acid sequence identity with the hydroxylase (HspB) fromPseudomonas putidastrain S16, whereas the specific activity of VppD is ∼10-fold higher than that of HspB. VppE is responsible for the transformation of 2,5-dihydroxypyridine. Sequence alignment and phylogenetic analysis suggested that the VPP pathway, which evolved independently from nicotinic acid degradation, might have a closer relationship with the pyrrolidine pathway. The proteins and functional pathway identified here provide a sound basis for future studies aimed at a better understanding of molecular principles of nicotine degradation.

scholarly journals SCO-1, a Novel Plasmid-Mediated Class A β-Lactamase with Carbenicillinase Characteristics from Escherichia coli

2007 ◽  
Vol 51 (6) ◽  
pp. 2185-2188 ◽  
Author(s):  
C. C. Papagiannitsis ◽  
A. Loli ◽  
L. S. Tzouvelekis ◽  
E. Tzelepi ◽  
G. Arlet ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Amino Acid Sequence Identity ◽  
Sequence Identity ◽  
Class A

ABSTRACT A novel class A β-lactamase (SCO-1) encoded by an 80-kb self-transferable plasmid from Escherichia coli is described. The interaction of SCO-1 with β-lactams was similar to that of the CARB-type enzymes. Also, SCO-1 exhibited a 51% amino acid sequence identity with the RTG subgroup of chromosomal carbenicillinases (RTG-1, CARB-5, and CARB-8).

RAA enzyme is a new family of class A extended-spectrum β-lactamase from the Riemerella anatipestifer RCAD0122 strain

2022 ◽  
Author(s):  
Hongyan Luo ◽  
Dekang Zhu ◽  
Mengru Li ◽  
Yunhan Tang ◽  
Wenyu Zhang ◽  
...  
Keyword(s):  
Amino Acid Sequence Identity ◽  
Natural Transformation ◽  
Kinetic Assay ◽  
Riemerella Anatipestifer ◽  
Sequence Identity ◽  
Class A ◽  
New Family ◽  
Extended Spectrum ◽  
Homologous Strain ◽  
Hydrolysis Activity

Whole genome sequencing of Riemerella anatipestifer isolate RCAD0122 revealed a chromosomally-located β-lactamases gene, bla RAA-1 , which encoded a novel class A extended-spectrum β-lactamases (ESBL), RAA-1. The RAA-1 shared ≤ 65% amino acid sequence identity with other characterized β-lactamases. The kinetic assay of native purified RAA-1 revealed ESBL-like hydrolysis activity. Furthermore, bla RAA-1 could be transferred to a homologous strain by natural transformation. However, the epidemiological study showed that the bla RAA-1 gene is not prevalent currently.

Sign in / Sign up

Export Citation Format

Share Document