scholarly journals Pre-existing soft modes of motion uniquely defined by native contact topology facilitate ligand binding to proteins

2011 ◽  
Vol 20 (10) ◽  
pp. 1645-1658 ◽  
Author(s):  
Lidio Meireles ◽  
Mert Gur ◽  
Ahmet Bakan ◽  
Ivet Bahar
Keyword(s):  
Ligand Binding ◽  
Contact Topology ◽  
Soft Modes ◽  
Native Contact

CarR, a MarR-family regulator from Corynebacterium glutamicum, modulated antibiotic and aromatic compound resistance

2019 ◽  
Vol 476 (21) ◽  
pp. 3141-3159 ◽  
Author(s):  
Meiru Si ◽  
Can Chen ◽  
Zengfan Wei ◽  
Zhijin Gong ◽  
GuiZhi Li ◽  
...  
Keyword(s):  
Stress Response ◽  
Ligand Binding ◽  
Corynebacterium Glutamicum ◽  
Conformational Changes ◽  
Cysteine Oxidation ◽  
Transcriptional Regulatory ◽  
Ligand Free ◽  
Redox Sensing

Abstract MarR (multiple antibiotic resistance regulator) proteins are a family of transcriptional regulators that is prevalent in Corynebacterium glutamicum. Understanding the physiological and biochemical function of MarR homologs in C. glutamicum has focused on cysteine oxidation-based redox-sensing and substrate metabolism-involving regulators. In this study, we characterized the stress-related ligand-binding functions of the C. glutamicum MarR-type regulator CarR (C. glutamicum antibiotic-responding regulator). We demonstrate that CarR negatively regulates the expression of the carR (ncgl2886)–uspA (ncgl2887) operon and the adjacent, oppositely oriented gene ncgl2885, encoding the hypothetical deacylase DecE. We also show that CarR directly activates transcription of the ncgl2882–ncgl2884 operon, encoding the peptidoglycan synthesis operon (PSO) located upstream of carR in the opposite orientation. The addition of stress-associated ligands such as penicillin and streptomycin induced carR, uspA, decE, and PSO expression in vivo, as well as attenuated binding of CarR to operator DNA in vitro. Importantly, stress response-induced up-regulation of carR, uspA, and PSO gene expression correlated with cell resistance to β-lactam antibiotics and aromatic compounds. Six highly conserved residues in CarR were found to strongly influence its ligand binding and transcriptional regulatory properties. Collectively, the results indicate that the ligand binding of CarR induces its dissociation from the carR–uspA promoter to derepress carR and uspA transcription. Ligand-free CarR also activates PSO expression, which in turn contributes to C. glutamicum stress resistance. The outcomes indicate that the stress response mechanism of CarR in C. glutamicum occurs via ligand-induced conformational changes to the protein, not via cysteine oxidation-based thiol modifications.

Soft-modes in displacive transitions

1971 ◽  
Vol 32 (8-9) ◽  
pp. 657-670 ◽  
Author(s):  
S. Aubry ◽  
R. Pick
Keyword(s):  
Soft Modes

TBG MEASUREMENTS BY COMPETITIVE LIGAND BINDING ASSAY (CLBA)

1975 ◽  
Vol 80 (1_Suppla) ◽  
pp. S15
Author(s):  
K. H. Rudorff ◽  
H. J. Kröll ◽  
J. Herrmann
Keyword(s):  
Ligand Binding ◽  
Binding Assay ◽  
Ligand Binding Assay ◽  
Competitive Ligand
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