Insight into the stability of the hydrophobic binding proteins of Escherichia coli: assessing the proteins for use as biosensors.
Spectroscopic methods were used to monitor the unfolding of the leucine specific (LS) and the leucine-isoleucine-valine (LIV) binding proteins. Our studies indicate that ligand-free protein undergoes a simple two-state unfolding, whereas the protein-ligand complex undergoes a three-state unfolding model. Ligand binding causes significant stabilization of both proteins. There is correlation between ligand hydrophobicity and protein stabilization: the most hydrophobic ligand, isoleucine, causes the most significant stabilization of LIV protein. A disulfide bond present in N-domain of both proteins makes a large contribution to the protein stability of these periplasmic binding receptors.
D001426:Bacterial Proteins; D015374:Biosensing Techniques; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D008024:Ligands; D008958:Models, Molecular; D011489:Protein Denaturation; D017510:Protein Folding; D017459:Receptors, Amino Acid / Q000737:chemistry / Q000378:metabolism
D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D008024:Ligands; C488923:LivJ protein, E coli; D017459:Receptors, Amino Acid; C034181:leucine receptor; C028332:leucine-isoleucine-valine binding protein, bacteria