OHIO-1 β-lactamase mutants: Asp179Gly mutation confers resistance to ceftazidime

Rudin, Susan D.; Shlaes, David M.

doi:10.1111/j.1574-6968.1997.tb10439.x

Cited by 4 publications

(3 citation statements)

References 12 publications

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“…These include SHV-6 (D179A), SHV-8 (D179N), and SHV-24 (D179G), which confer resistance to ceftazidime (12). The role of Asp179 has been well studied (2,3,12). The X-ray crystal structure of the mutant with the D179N mutation of the PC1 ␤-lactamase shows a disordered ⍀ loop (5).…”

Section: Discussionmentioning

confidence: 99%

Novel SHV-Derived Extended-Spectrum β-Lactamase, SHV-57, That Confers Resistance to Ceftazidime but Not Cefazolin

Alba

Chang

et al. 2005

Antimicrob Agents Chemother

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A new SHV-derived extended-spectrum ␤-lactamase, SHV-57, that confers high-level resistance to ceftazidime but not cefotaxime or cefazolin was identified from a national surveillance study conducted in Taiwan in 1998. An Escherichia coli isolate resistant to ampicillin, cephalothin, and ceftazidime but sensitive to cefoxitin, ceftriaxone, cefotaxime, imipenem, and a narrow-spectrum cephem (cefazolin) was isolated from the urine of a patient treated with ␤-lactam antibiotics. Resistance to ␤-lactams was conjugatively transferred with a plasmid of about 50 kbp. The pI of this enzyme was 8.3. The sequence of the gene was determined, and the open reading frame of the gene was found to consist of 861 bases (GenBank accession number AY223863). Kinetic parameters showed that SHV-57 had a poor affinity to cefazolin. The K m value toward cefazolin (5.57 ؋ 10 3 M) was extremely high in comparison to those toward ceftazidime (30.9 M) and penicillin G (67 M), indicating its low affinity to cefazolin. Although the K m value of the ␤-lactamase inhibitor was too high for the study of catalytic activity (k cat ), indicating the low k cat of SHV-57, the SHV-57 carrier was highly susceptible to a ␤-lactam-␤-lactamase inhibitor combination. Comparison of the three-dimensional molecular model of SHV-57 with that of the SHV-1 ␤-lactamase suggests that the substitution of arginine for leucine-169 in the ⍀ loop is important for the substrate specificity.Since the first extended-spectrum ␤-lactamase (ESBL) was isolated in Germany in 1983 (11), TEM-, SHV-, CTX-, and OXA-type ESBLs have been described in various members of the family Enterobacteriaceae (G. A. Jacoby and K. Bush, http://www.lahey.org/studies/webt.htm). Most of the ESBLs have altered hydrolytic activities compared with those of the classical enzymes TEM-1, TEM-2, and SHV-1 as a result of amino acid changes in different specific positions (10, 17). SHV-1 is a narrow-spectrum ␤-lactamase with activity against penicillins. The first extended-spectrum SHV enzyme was described in 1985 and was named SHV-2 (10). The serine at amino acid position 238 was found to be replaced by glycine in SHV-1 and was found to cause resistance to extended-spectrum ␤-lactams. Since then, many SHV-type ESBLs have been reported. Most of the substitutions are at Ambler position 179 or 238, alone or in combination with alterations at positions 35 and 240, which are important for substrate extension (G. A. Jacoby and K. Bush, http://www.lahey.org/studies/webt.htm). X-ray crystallography shows that mutations which cause amino acid changes on or close to the ⍀ loop of the enzyme are highly correlated to resistance to extended-spectrum ␤-lactams (12). The mutation at Gly238 has frequently been reported in SHVtype ESBLs. It causes resistance to various antibiotics, ranging from narrow-spectrum cephalosporins (cefazolin) to extendedspectrum cephalosporins (ceftazidime and cefotaxime). However, resistance only to extended-spectrum cephalosporins with susceptibility to narrow-spectrum cephalosporins is rarely...

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Section: Discussionmentioning

confidence: 99%

Novel SHV-Derived Extended-Spectrum β-Lactamase, SHV-57, That Confers Resistance to Ceftazidime but Not Cefazolin

Alba

Chang

et al. 2005

Antimicrob Agents Chemother

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“…Over the past decades, bacteria managed to respond to the high and constantly changing antibiotic selection pressures by evolving β‐lactamases able to degrade novel antibiotics. New β‐lactam resistant strains are frequently reported, with sometimes only one point mutation in the enzyme leading to a new catalytic function 10–13 . This room for evolution in β‐lactamases is reflected in the low amino acid conservation.…”

Section: Introductionmentioning

confidence: 99%

“…New β-lactam resistant strains are frequently reported, with sometimes only one point mutation in the enzyme leading to a new catalytic function. [10][11][12][13] This room for evolution in β-lactamases is reflected in the low amino acid conservation. A sequence alignment of the β-lactamase from Mycobacterium tuberculosis (Mtb), BlaC, the object of this study, with 493 other class A β-lactamases shows 49%-81% identity.…”

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confidence: 99%

The roles of highly conserved, non‐catalytic residues in class A β‐lactamases

Chikunova

Ubbink

2022

Protein Science

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Evolution minimizes the number of highly conserved amino acid residues in proteins to ensure evolutionary robustness and adaptability. The roles of all highly conserved, non-catalytic residues, 11% of all residues, in class A β-lactamase were analyzed by studying the effect of 146 mutations on in cell and in vitro activity, folding, structure, and stability. Residues around the catalytic residues (second shell) contribute to fine-tuning of the active site structure. Mutations affect the structure over the entire active site and can result in stable but inactive protein. Conserved residues farther away (third shell) ensure a favorable balance of folding versus aggregation or stabilize the folded form over the unfolded state. Once folded, the mutant enzymes are stable and active and show only localized structural effects. These residues are found in clusters, stapling secondary structure elements. The results give an integral picture of the different roles of essential residues in enzymes.

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Asp179 in the class A β‐lactamase from Mycobacterium tuberculosis is a conserved yet not essential residue due to epistasis

et al. 2023

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Conserved residues are often considered essential for function, and substitutions in such residues are expected to have a negative influence on the properties of a protein. However, mutations in a few highly conserved residues of the β‐lactamase from Mycobacterium tuberculosis, BlaC, were shown to have no or only limited negative effect on the enzyme. One such mutant, D179N, even conveyed increased ceftazidime resistance upon bacterial cells, while displaying good activity against penicillins. The crystal structures of BlaC D179N in resting state and in complex with sulbactam reveal subtle structural changes in the Ω‐loop as compared to the structure of wild‐type BlaC. Introducing this mutation in four other β‐lactamases, CTX‐M‐14, KPC‐2, NMC‐A and TEM‐1, resulted in decreased antibiotic resistance for penicillins and meropenem. The results demonstrate that the Asp in position 179 is generally essential for class A β‐lactamases but not for BlaC, which can be explained by the importance of the interaction with the side chain of Arg164 that is absent in BlaC. It is concluded that Asp179 though conserved is not essential in BlaC, as a consequence of epistasis.

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OHIO-1 β-lactamase mutants: Asp179Gly mutation confers resistance to ceftazidime

Cited by 4 publications

References 12 publications

Novel SHV-Derived Extended-Spectrum β-Lactamase, SHV-57, That Confers Resistance to Ceftazidime but Not Cefazolin

Novel SHV-Derived Extended-Spectrum β-Lactamase, SHV-57, That Confers Resistance to Ceftazidime but Not Cefazolin

The roles of highly conserved, non‐catalytic residues in class A β‐lactamases

Asp179 in the class A β‐lactamase from Mycobacterium tuberculosis is a conserved yet not essential residue due to epistasis

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