1nrf: Difference between revisions

Line 1:

[[Image:1nrf.gif|left|200px]]<br /><applet load="1nrf" size="~~450~~" color="white" frame="true" align="right" spinBox="true"

[[Image:1nrf.gif|left|200px]]<br /><applet load="1nrf" size="350" color="white" frame="true" align="right" spinBox="true"

caption="1nrf, resolution 2.50Å" />

'''C-terminal domain of the Bacillus licheniformis BlaR penicillin-receptor'''<br />

==Overview==

As in several staphylococci, the synthesis of the Bacillus licheniformis, 749/I beta-lactamase is an inducible phenomenon regulated by a, signal-transducing membrane protein BlaR. The C-terminal domain of this, multimodular protein is an extracellular domain which specifically, recognizes beta-lactam antibiotics. When it binds a beta-lactam, a signal, is transmitted by the transmembrane region to the intracellular loops. In, response, the hydrolytic activity of the BlaR large cytoplasmic L3 loop is, induced, and a cascade of reactions is generated, leading to the, transcription of the beta-lactamase gene. Here, we describe the crystal, structure of the extracellular penicillin-receptor domain of BlaR, (residues 346-601) at 2.5 A resolution in order to understand why this, domain, whose folding is very similar to that of class D beta-lactamases, behaves as a highly sensitive penicillin-binding protein rather than a, beta-lactamase. Two residues of the BlaR C-terminal domain, Thr452 and, Thr542, modify the hydrophobic characteristic of the class D, beta-lactamase active site. Both residues seem to be in part responsible, for the lack of beta-lactamase activity of the BlaR protein due to the, stability of the acyl-enzyme. Although further experimental data are, needed to fully understand the transmembrane induction process, the, comparison of the BlaR sensor domain structure with those of class D, beta-lactamase complexes and penicillin-binding proteins provides, interesting elements to hypothesize on possible signal transmission, mechanisms.

As in several staphylococci, the synthesis of the Bacillus licheniformis 749/I beta-lactamase is an inducible phenomenon regulated by a signal-transducing membrane protein BlaR. The C-terminal domain of this multimodular protein is an extracellular domain which specifically recognizes beta-lactam antibiotics. When it binds a beta-lactam, a signal is transmitted by the transmembrane region to the intracellular loops. In response, the hydrolytic activity of the BlaR large cytoplasmic L3 loop is induced, and a cascade of reactions is generated, leading to the transcription of the beta-lactamase gene. Here, we describe the crystal structure of the extracellular penicillin-receptor domain of BlaR (residues 346-601) at 2.5 A resolution in order to understand why this domain, whose folding is very similar to that of class D beta-lactamases, behaves as a highly sensitive penicillin-binding protein rather than a beta-lactamase. Two residues of the BlaR C-terminal domain, Thr452 and Thr542, modify the hydrophobic characteristic of the class D beta-lactamase active site. Both residues seem to be in part responsible for the lack of beta-lactamase activity of the BlaR protein due to the stability of the acyl-enzyme. Although further experimental data are needed to fully understand the transmembrane induction process, the comparison of the BlaR sensor domain structure with those of class D beta-lactamase complexes and penicillin-binding proteins provides interesting elements to hypothesize on possible signal transmission mechanisms.

==About this Structure==

1NRF is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_licheniformis Bacillus licheniformis]. Full crystallographic information is available from [http://~~ispc~~.weizmann.ac.il/oca-bin/ocashort?id=1NRF OCA].

1NRF is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_licheniformis Bacillus licheniformis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NRF OCA].

==Reference==

Line 15:

[[Category: Brans, A.]]

[[Category: Charlier, P.]]

[[Category: Columbo, M.L.]]

[[Category: Columbo, M L.]]

[[Category: Fonze, E.]]

[[Category: Frere, J.M.]]

[[Category: Frere, J M.]]

[[Category: Joris, B.]]

[[Category: Kerff, F.]]

Line 26:

[[Category: penicillin-receptor]]

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@@ Line 1: / Line 1: @@
-[[Image:1nrf.gif|left|200px]]<br /><applet load="1nrf" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1nrf.gif|left|200px]]<br /><applet load="1nrf" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1nrf, resolution 2.50&Aring;" />
 '''C-terminal domain of the Bacillus licheniformis BlaR penicillin-receptor'''<br />
 ==Overview==
-As in several staphylococci, the synthesis of the Bacillus licheniformis, 749/I beta-lactamase is an inducible phenomenon regulated by a, signal-transducing membrane protein BlaR. The C-terminal domain of this, multimodular protein is an extracellular domain which specifically, recognizes beta-lactam antibiotics. When it binds a beta-lactam, a signal, is transmitted by the transmembrane region to the intracellular loops. In, response, the hydrolytic activity of the BlaR large cytoplasmic L3 loop is, induced, and a cascade of reactions is generated, leading to the, transcription of the beta-lactamase gene. Here, we describe the crystal, structure of the extracellular penicillin-receptor domain of BlaR, (residues 346-601) at 2.5 A resolution in order to understand why this, domain, whose folding is very similar to that of class D beta-lactamases, behaves as a highly sensitive penicillin-binding protein rather than a, beta-lactamase. Two residues of the BlaR C-terminal domain, Thr452 and, Thr542, modify the hydrophobic characteristic of the class D, beta-lactamase active site. Both residues seem to be in part responsible, for the lack of beta-lactamase activity of the BlaR protein due to the, stability of the acyl-enzyme. Although further experimental data are, needed to fully understand the transmembrane induction process, the, comparison of the BlaR sensor domain structure with those of class D, beta-lactamase complexes and penicillin-binding proteins provides, interesting elements to hypothesize on possible signal transmission, mechanisms.
+As in several staphylococci, the synthesis of the Bacillus licheniformis 749/I beta-lactamase is an inducible phenomenon regulated by a signal-transducing membrane protein BlaR. The C-terminal domain of this multimodular protein is an extracellular domain which specifically recognizes beta-lactam antibiotics. When it binds a beta-lactam, a signal is transmitted by the transmembrane region to the intracellular loops. In response, the hydrolytic activity of the BlaR large cytoplasmic L3 loop is induced, and a cascade of reactions is generated, leading to the transcription of the beta-lactamase gene. Here, we describe the crystal structure of the extracellular penicillin-receptor domain of BlaR (residues 346-601) at 2.5 A resolution in order to understand why this domain, whose folding is very similar to that of class D beta-lactamases, behaves as a highly sensitive penicillin-binding protein rather than a beta-lactamase. Two residues of the BlaR C-terminal domain, Thr452 and Thr542, modify the hydrophobic characteristic of the class D beta-lactamase active site. Both residues seem to be in part responsible for the lack of beta-lactamase activity of the BlaR protein due to the stability of the acyl-enzyme. Although further experimental data are needed to fully understand the transmembrane induction process, the comparison of the BlaR sensor domain structure with those of class D beta-lactamase complexes and penicillin-binding proteins provides interesting elements to hypothesize on possible signal transmission mechanisms.
 ==About this Structure==
-NRF is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_licheniformis Bacillus licheniformis]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1NRF OCA].
+NRF is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_licheniformis Bacillus licheniformis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NRF OCA].
 ==Reference==
@@ Line 15: / Line 15: @@
 [[Category: Brans, A.]]
 [[Category: Charlier, P.]]
-[[Category: Columbo, M.L.]]
+[[Category: Columbo, M L.]]
 [[Category: Fonze, E.]]
-[[Category: Frere, J.M.]]
+[[Category: Frere, J M.]]
 [[Category: Joris, B.]]
 [[Category: Kerff, F.]]
@@ Line 26: / Line 26: @@
 [[Category: penicillin-receptor]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 22:30:21 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:09:12 2008''