Discrete steps in sensing of β-lactam antibiotics by the BlaR1 protein of the methicillin-resistant
            <i>Staphylococcus aureus</i>
            bacterium

Thumanu, Kanjana; Cha, Jooyoung; Fisher, Jed F.; Perrins, Richard; Mobashery, Shahriar; Wharton, Christopher W.

doi:10.1073/pnas.0601971103

Cited by 49 publications

(58 citation statements)

References 24 publications

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“…As class D ␤-lactamases enjoy symmetry in catalysis (42), N-carboxylated lysine promotes/activates a water molecule for the deacylation event as well, a function that BlaR1 is incapable of performing as it experiences N-decarboxylation on acylation by the antibiotic. It is known that the N-decarboxylated Lys-392 of BlaR1 is incapable of promoting the deacylation step (8). However, our simulations of the dynamics of the BlaR1 sensor domain showed that N-carboxylated Lys-392 is well poised to promote acylation of Ser-389 only after it assumes a conformation that closely approximates that of the class D ␤-lactamase.…”

Section: Discussionmentioning

confidence: 68%

“…The protein with the unmodified Lys-392 is not active, as disclosed in an earlier study (8). Lys-392 has rotated nearly 180°about its ␦ carbon in the protein molecule with N-carboxylated lysine.…”

Section: Structure Of the Native Blarmentioning

confidence: 78%

“…Antibiotic acylates Ser-389, resulting in an acyl-protein complex. Furthermore, we had detected by spectroscopy that the sensor domain experiences the uncommon posttranslational modification of N-carboxylation at the side chain of Lys-392, a residue within the antibioticbinding site (8,9). This is the product of reaction of carbon dioxide with the side-chain amine of the lysine (Fig.…”

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confidence: 99%

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Lysine Nζ-Decarboxylation Switch and Activation of the β-Lactam Sensor Domain of BlaR1 Protein of Methicillin-resistant Staphylococcus aureus

Borbulevych

Kumarasiri

Wilson

et al. 2011

Journal of Biological Chemistry

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The integral membrane protein BlaR1 of methicillin-resistant Staphylococcus aureus senses the presence of ␤-lactam antibiotics in the milieu and transduces the information to the cytoplasm, where the biochemical events that unleash induction of antibiotic resistance mechanisms take place. We report herein by two-dimensional and three-dimensional NMR experiments of the sensor domain of BlaR1 in solution and by determination of an x-ray structure for the apo protein that Lys-392 of the antibiotic-binding site is posttranslationally modified by N -carboxylation. Additional crystallographic and NMR data reveal that on acylation of Ser-389 by antibiotics, Lys-392 experiences N -decarboxylation. This unique process, termed the lysine N -decarboxylation switch, arrests the sensor domain in the activated ("on") state, necessary for signal transduction and all the subsequent biochemical processes. We present structural information on how this receptor activation process takes place, imparting longevity to the antibiotic-receptor complex that is needed for the induction of the antibiotic-resistant phenotype in methicillin-resistant S. aureus.An antibiotic-resistant bacterium, which emerged first in the United Kingdom in 1961, disseminated rapidly globally and came to be known as methicillin-resistant Staphylococcus aureus (MRSA) 3 (1, 2). Modern forms of MRSA are broadly resistant to antibiotics of various classes, but resistance to ␤-lactam antibiotics (penicillins, cephalosporins, and carbapenems, among others) is most insidious as it encompasses virtually all commercially available members of the class (3-5). The mechanistic basis of resistance to ␤-lactam antibiotics in MRSA is complex for which the antibiotic sensor/signal transducer protein BlaR1 is a key player (4). The surface domain of BlaR1 detects the presence of the ␤-lactam antibiotic in the milieu. Once the antibiotic complex with the sensor domain forms, it initiates transduction of the information on antibiotic recognition to the cytoplasmic domain, which is a zincdependent protease (Fig. 1A) (6). The protease domain degrades the gene repressor BlaI to derepress expression of the antibiotic resistance genes for ␤-lactams, including that for BlaR1 itself, for manifestation of the MRSA antibiotic resistance phenotype (6, 7).The recognition at the surface domain is not merely a complex formation between the antibiotic and the sensor domain, but rather involves covalent chemistry. Antibiotic acylates Ser-389, resulting in an acyl-protein complex. Furthermore, we had detected by spectroscopy that the sensor domain experiences the uncommon posttranslational modification of N-carboxylation at the side chain of Lys-392, a residue within the antibioticbinding site (8,9). This is the product of reaction of carbon dioxide with the side-chain amine of the lysine (Fig. 1B). Conspicuously, the N-carboxylated lysine has not been seen in the x-ray structures for the sensor domain (10 -12).We document herein for the first time by x-ray crystallography that the apo form of ...

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Section: Discussionmentioning

confidence: 68%

Section: Structure Of the Native Blarmentioning

confidence: 78%

mentioning

confidence: 99%

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Lysine Nζ-Decarboxylation Switch and Activation of the β-Lactam Sensor Domain of BlaR1 Protein of Methicillin-resistant Staphylococcus aureus

Borbulevych

Kumarasiri

Wilson

et al. 2011

Journal of Biological Chemistry

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“…Its role as a ␤-lactam sensor/signal transducer is fully appreciated, but the details of its molecular events are less understood. The process of ␤-lactam sensing is elaborate, and it involves an uncommon N-carboxylated lysine that experiences N-decarboxylation on acylation of the protein with the antibiotic (2,4). This N-decarboxylation of the lysine within the antibiotic-binding site affords longevity to the acyl-protein species, which in turn initiates signaling events from the surface of the membrane to the cytoplasm.…”

Section: Discussionmentioning

confidence: 99%

“…1). Antibiotic acylates the C-terminal sensor domain located on the surface of the plasma membrane by a mechanism involving a surface loop of the protein (1) and an elaborate process that leads to N-decarboxylation of a lysine within the antibiotic-binding site (2)(3)(4). The acylated species enjoys a longevity that often exceeds the doubling time of most S. aureus strains; hence, a single BlaR1 modification by the antibiotic is sufficient for the entire bacterial generation (5).…”

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confidence: 99%