TY - JOUR
T1 - The discrete steps in sensing of beta-lactam antibiotics by the BlaR1 protein of MRSA by rapid infrared spectroscopy
AU - Thumanu, K
AU - Cha, J
AU - Fisher, JF
AU - Perrins, Richard
AU - Mobashery, S
AU - Wharton, Christopher
PY - 2006/7/11
Y1 - 2006/7/11
N2 - Chemical sensing by cell-surface receptors to effect signal transduction is a ubiquitous biological event. Despite extensive structural biochemical study, detailed knowledge of how signal transduction occurs is largely lacking. We report herein a kinetic and structural study, obtained by stopped-flow IR spectroscopy, of the activation of the BlaR1 receptor of the Staphylococcus aureus bacterium by beta-lactam antibiotics. The cell-surface BlaR1 receptor alerts the bacterium to the presence of beta-lactam antibiotics, resulting in expression of the gene for a beta-lactamase enzyme. This enzyme hydrolytically destroys the remaining beta-lactam antibiotics. IR spectroscopic interrogation of the beta-lactam-BlaR1 receptor reaction has allowed the simultaneous measurement of the chemical events of receptor recognition of the P-lactam and the characterization of the conformational changes in the BlaR1 receptor that result. The key chemical events in beta-lactam recognition are serine acylation and subsequent irreversible decarboxylation of the BlaR1 active site lysine carbamate. Both events are observed by stopped-flow IR kinetics and C-13 isotope-edited IR spectroscopy. The secondary structural changes in the BlaR1 receptor conformation that occur as a consequence of this acylation/decarboxylation are predicted to correlate to the signal transduction event accomplished by this receptor.
AB - Chemical sensing by cell-surface receptors to effect signal transduction is a ubiquitous biological event. Despite extensive structural biochemical study, detailed knowledge of how signal transduction occurs is largely lacking. We report herein a kinetic and structural study, obtained by stopped-flow IR spectroscopy, of the activation of the BlaR1 receptor of the Staphylococcus aureus bacterium by beta-lactam antibiotics. The cell-surface BlaR1 receptor alerts the bacterium to the presence of beta-lactam antibiotics, resulting in expression of the gene for a beta-lactamase enzyme. This enzyme hydrolytically destroys the remaining beta-lactam antibiotics. IR spectroscopic interrogation of the beta-lactam-BlaR1 receptor reaction has allowed the simultaneous measurement of the chemical events of receptor recognition of the P-lactam and the characterization of the conformational changes in the BlaR1 receptor that result. The key chemical events in beta-lactam recognition are serine acylation and subsequent irreversible decarboxylation of the BlaR1 active site lysine carbamate. Both events are observed by stopped-flow IR kinetics and C-13 isotope-edited IR spectroscopy. The secondary structural changes in the BlaR1 receptor conformation that occur as a consequence of this acylation/decarboxylation are predicted to correlate to the signal transduction event accomplished by this receptor.
UR - http://www.scopus.com/inward/record.url?scp=33746039712&partnerID=8YFLogxK
U2 - 10.1073/pnas.0601971103
DO - 10.1073/pnas.0601971103
M3 - Article
C2 - 16815972
SN - 1091-6490
VL - 103
SP - 10630
EP - 10635
JO - National Academy of Sciences. Proceedings
JF - National Academy of Sciences. Proceedings
ER -