scholarly journals Carboxy groups as essential residues in β-lactamases

1986 ◽  
Vol 240 (1) ◽  
pp. 215-219 ◽  
Author(s):  
C Little ◽  
E L Emanuel ◽  
J Gagnon ◽  
S G Waley

Beta-lactamases are divided into classes A, B and C on the basis of their amino acid sequences. Beta-Lactamases were incubated at pH 4.0 with the carboxy-group reagent 1-(3-dimethylaminopropyl)-3-ethylcarbodi-imide plus a coloured nucleophile and the extents of inactivation and nucleophile incorporation were monitored. Two class A enzymes (from Bacillus cereus and Bacillus licheniformis) and two class C enzymes (from Enterobacter cloacae P99 and Pseudomonas aeruginosa) were examined. All four enzymes were inactivated, with total inactivation corresponding to the incorporation of approx. 2-3 mol of nucleophile/mol of enzyme. In the case of beta-lactamase I from Bacillus cereus, some 53% of the incorporated nucleophile was located on glutamic acid-168 in the amino acid sequence.

1975 ◽  
Vol 147 (2) ◽  
pp. 313-326 ◽  
Author(s):  
D R Thatcher

The chemical structure of the extracellular beta-lactamase I of Bacillus cereus 569/H was investigated. Three electrophoretically homogenous charge variants of this enzyme were isolated and amino acid analysis of each revealed no significant differences. However, a degree of N-terminal heterogeneity was found by direct end-group modification of the protein and also on alignment of peptides from tryptic and chymotryptic digestion. The N-terminal heterogeneity observed was great enough to explain the production of the beta-lactamase I isoenzymes which are probably produced by postsynthesis modification of a single gene product. Over 80% of the amino acid sequence of beta-lactamase I was determined by the detailed analysis of peptides derived from tryptic, chymotryptic and thermolytic digests. Five polypeptide fragments were constructed from these data and aligned by comparison with the known amino acid sequences of the penicillinases produced by Bacillus licheniformis and Staphylococcus aureus (Ambler & Meadway, 1969). About 60% of the proposed sequence was identical with that of B. licheniformis penicillinase, whereas the S. aureus enzyme had only about 40% of its residues in common with beta-lactamase I. These results are discussed with reference to the possible evolutionary relationships existing between known beta-lactamases. Detailed evidence for the amino acid sequence proposed has been deposited as Supplementary Publication SUP 50044 (27 pages) at the British Library (Lending Division), Boston Spa, Wetherby, W. Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1975), 145, 5.


1996 ◽  
Vol 40 (3) ◽  
pp. 616-620 ◽  
Author(s):  
A Bauernfeind ◽  
I Stemplinger ◽  
R Jungwirth ◽  
P Mangold ◽  
S Amann ◽  
...  

Plasmidic extended-spectrum beta-lactamases of Ambler class A are mostly inactive against ceftibuten. Salmonella typhimurium JMC isolated in Argentina harbors a bla gene located on a plasmid (pMVP-5) which confers transferable resistance to oxyiminocephalosporins, aztreonam, and ceftibuten. The beta-lactamase PER-2 (formerly ceftibutenase-1; CTI-1) is highly susceptible to inhibition by clavulanate and is located at a pI of 5.4 after isoelectric focusing. The blaPER-2 gene was cloned and sequenced. The nucleotide sequence of a 2.2-kb insert in vector pBluescript includes an open reading frame of 927 bp. Comparison of the deduced amino acid sequence of PER-2 with those of other beta-lactamases indicates that PER-2 is not closely related to TEM or SHV enzymes (25 to 26% homology). PER-2 is most closely related to PER-1 (86.4% homology), an Ambler class A enzyme first detected in Pseudomonas aeruginosa. An enzyme with an amino acid sequence identical to that of PER-1, meanwhile, was found in various members of the family Enterobacteriaceae isolated from patients in Turkey. Our data indicate that PER-2 and PER-1 represent a new group of Ambler class A extended-spectrum beta-lactamases. PER-2 so far has been detected only in pathogens (S. typhimurium, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis) isolated from patients in South America, while the incidence of PER-1-producing strains so far has been restricted to Turkey, where it occurs both in members of the family Enterobacteriaceae and in P. aeruginosa.


1988 ◽  
Vol 253 (2) ◽  
pp. 323-328 ◽  
Author(s):  
J Monks ◽  
S G Waley

The interaction between imipenem, a carbapenem antibiotic, and two representative beta-lactamases has been studied. The first enzyme was beta-lactamase I, a class-A beta-lactamase from Bacillus cereus; imipenem behaved as a slow substrate (kcat. 6.7 min-1, Km 0.4 mM at 30 degrees C and at pH 7) that reacted by a branched pathway. There was transient formation of an altered species formed in a reversible reaction; this species was probably an acyl-enzyme in a slightly altered, but considerably more labile, conformation. The kinetics of the reaction were investigated by measuring both the concentration of the substrate and the activity of the enzyme, which fell and then rose again more slowly. The second enzyme was the chromosomal class-C beta-lactamase from Pseudomonas aeruginosa; imipenem was a substrate with a low kcat. (0.8 min-1) and a low Km (0.7 microM). Possible implications for the clinical use of imipenem are considered.


1996 ◽  
Vol 40 (2) ◽  
pp. 509-513 ◽  
Author(s):  
A Bauernfeind ◽  
I Stemplinger ◽  
R Jungwirth ◽  
S Ernst ◽  
J M Casellas

Amino acid sequences determined either by protein sequencing or by DNA sequencing are identical for cefotaximases CTX-M-1 and MEN-1, whereas CTX-M-2 is 84% identical to CTX-M-1/MEN-1. Both beta-lactamases are distantly related to other plasmidic class A enzymes (homology to TEM-1 is 38.1% for CTX-M-1/MEN-1 and 36.5% for CTX-M-2); the closest relationship was with the chromosomal beta-lactamase of Klebsiella oxytoca E23004 (homologies of 74.5% for CTX-M-1/MEN-1 and 77.9% for CTX-M-2). The cefotaximases CTX-M-1/MEN-1 and CTX-M-2 represent two members of a new subgroup of plasmidic class A beta-lactamases.


1988 ◽  
Vol 250 (3) ◽  
pp. 753-760 ◽  
Author(s):  
M Galleni ◽  
F Lindberg ◽  
S Normark ◽  
S Cole ◽  
N Honore ◽  
...  

The sequences of three Enterobacter cloacae ampC beta-lactamase genes have been determined. The deduced amino acid sequences are very similar: out of a total of 361 residues, only eight positions were found to be variable, and several mutations yielded residues with very similar properties. The kinetic properties of two of the enzymes were not significantly different. The three enzymes also exhibited a high degree of homology (greater than 70%) with the ampC beta-lactamases of Escherichia coli K12 and Citrobacter freundii, confirming the homogeneity of class-C beta-lactamases.


1973 ◽  
Vol 131 (3) ◽  
pp. 485-498 ◽  
Author(s):  
R. P. Ambler ◽  
Margaret Wynn

The amino acid sequences of the cytochromes c-551 from three species of Pseudomonas have been determined. Each resembles the protein from Pseudomonas strain P6009 (now known to be Pseudomonas aeruginosa, not Pseudomonas fluorescens) in containing 82 amino acids in a single peptide chain, with a haem group covalently attached to cysteine residues 12 and 15. In all four sequences 43 residues are identical. Although by bacteriological criteria the organisms are closely related, the differences between pairs of sequences range from 22% to 39%. These values should be compared with the differences in the sequence of mitochondrial cytochrome c between mammals and amphibians (about 18%) or between mammals and insects (about 33%). Detailed evidence for the amino acid sequences of the proteins has been deposited as Supplementary Publication SUP 50015 at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1973), 131, 5.


1985 ◽  
Vol 229 (3) ◽  
pp. 791-797 ◽  
Author(s):  
R Bicknell ◽  
E L Emanuel ◽  
J Gagnon ◽  
S G Waley

The production and purification of a tetrameric zinc beta-lactamase from Pseudomonas maltophilia IID 1275 were greatly improved. Three charge variants were isolated by chromatofocusing. The subunits each contain two atomic proportions of zinc and (in two of the variants) one residue of cysteine. The thiol group is not required for activity, nor does it appear to bind to the metal. Replacement of zinc by cobalt, cadmium or nickel takes place at a measurable rate, and gives enzymes that are less active than the zinc enzyme. The properties of this enzyme differ from those of the other known zinc beta-lactamase, beta-lactamase II from Bacillus cereus. The amino acid sequence of the N-terminal 32 residues was determined; there is no similarity to the N-terminal sequences of other beta-lactamases.


1997 ◽  
Vol 41 (11) ◽  
pp. 2547-2549 ◽  
Author(s):  
L Bret ◽  
E B Chaibi ◽  
C Chanal-Claris ◽  
D Sirot ◽  
R Labia ◽  
...  

A novel inhibitor-resistant TEM (IRT) beta-lactamase was detected in an Escherichia coli isolate resistant to amoxicillin-clavulanate and susceptible to cephalothin. The substrate and inhibitor profiles of this beta-lactamase were similar to those of IRT-1 and IRT-2. The novel IRT's bla gene was sequenced, and the deduced amino acid sequence showed the amino acid replacement Arg for His-244 of the TEM-1 sequence. Substitutions for Arg-244 have been reported in three TEM-1 mutants: IRT-1 (which corresponds to TEM-31) (Cys), IRT-2/TEM-30 (Ser), and TEM-41 (Thr). We designated this novel beta-lactamase, which corresponds to TEM-51, IRT-15.


1997 ◽  
Vol 41 (3) ◽  
pp. 715-716 ◽  
Author(s):  
C Chanal-Claris ◽  
D Sirot ◽  
L Bret ◽  
P Chatron ◽  
R Labia ◽  
...  

A novel extended-spectrum TEM-type beta-lactamase was detected in an Escherichia coli isolate which was resistant to ceftazidime and susceptible to cephalothin. The corresponding bla gene was sequenced. The deduced amino acid sequence showed the following three amino acid replacements with respect to the TEM-2 sequence: Glu-->Lys-104, Arg-->Ser-164, and Glu-->Lys-240. Since it confers a ceftazidimase-type resistance phenotype, we propose for this novel enzyme the designation CAZ-9, corresponding to TEM-46 in the sequential numbering scheme of TEM beta-lactamases.


1991 ◽  
Vol 279 (1) ◽  
pp. 111-114 ◽  
Author(s):  
J Martin Villacorta ◽  
P Arriaga ◽  
J Laynez ◽  
M Menendez

The influence of C-6 alpha- or C-7 alpha-methoxylation of the beta-lactam ring in the catalytic action of class A and B beta-lactamases has been investigated. For this purpose the kinetic behaviour of beta-lactamases I (class A) and II (class B) from Bacillus cereus was analysed by using several cephamycins, moxalactam, temocillin and related antibiotics. These compounds behaved as poor substrates for beta-lactamase II, with high Km values and very low catalytic efficiencies. In the case of beta-lactamase I, the substitution of a methoxy group for a H atom at C-7 alpha or C-6 alpha decreased the affinity of the substrates for the enzyme. Furthermore, the acylation of cephamycins was completely blocked, whereas that of penicillins was slowed down by a factor of 10(4)-10(5), acylation being the rate-determining step of the process.


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