scholarly journals The Two NK-1 Binding Sites Correspond to Distinct, Independent, and Non-Interconvertible Receptor Conformational States As Confirmed by Plasmon-Waveguide Resonance Spectroscopy

Biochemistry ◽  
2006 ◽  
Vol 45 (16) ◽  
pp. 5309-5318 ◽  
Author(s):  
Isabel D. Alves ◽  
Diane Delaroche ◽  
Bernard Mouillac ◽  
Zdzislaw Salamon ◽  
Gordon Tollin ◽  
...  
Keyword(s):  
Binding Sites ◽  
Resonance Spectroscopy ◽  
Conformational States ◽  
Waveguide Resonance

Allosteric theory

Hemoglobin ◽  
2018 ◽  
pp. 42-57
Author(s):  
Jay F. Storz
Keyword(s):  
Active Site ◽  
Binding Sites ◽  
Allosteric Regulation ◽  
Theoretical Models ◽  
State Model ◽  
Regulatory Control ◽  
Indirect Interaction ◽  
Protein Activity ◽  
Conformational States ◽  
Two State Model

Chapter 3 provides a brief overview of allostery, the modulation of protein activity that is caused by an indirect interaction between structurally remote binding sites. In this mode of intramolecular regulatory control, the binding of ligand at a protein’s active site is influenced by the binding of another ligand at a different site in the same protein. This interaction at a distance is mediated by a ligation-induced transition between alternative conformational states. Hemoglobin is regarded as the “allosteric paradigm,” and the oxygenation-linked transition between alternative quaternary conformations provides a textbook example of how allostery works. This chapter reviews different theoretical models, such as the Monod-Wyman-Changeux “two-state” model, to explain the allosteric regulation of hemoglobin function.

A Nuclear Magnetic Resonance Study of the Metal Binding Sites in Bacitracin

1975 ◽  
Vol 53 (12) ◽  
pp. 1250-1254 ◽  
Author(s):  
Roderick E. Wasylishen ◽  
Moira R. Graham
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Metal Binding ◽  
Binding Sites ◽  
Imidazole Ring ◽  
Nuclear Magnetic Resonance Study ◽  
Resonance Spectroscopy ◽  
Metal Binding Sites ◽  
Ph Values ◽  
Nuclear Magnetic

Carbon-13 nuclear magnetic resonance spectroscopy has been used to identify sites in bacitracin which bind Cu2+ and Mn2+. Results are presented which implicate the free carboxyl groups of the aspartic and glutamic acid residues and the imidazole ring of the histidine residue as metal complexation sites between pH 6 and 8. Evidence is presented which also indicates that the thiazoline ring of bacitracin binds Mn2+. Bacitracin does not bind Cu2+ or Mn2+ at pH values of 2.5 or less.

1H -NMRInvestigations on the Hydrogen Bond Formation between the Tranquilizers Diazepam and Nitrazepam and Some Nucleobases

1978 ◽  
Vol 33 (11-12) ◽  
pp. 870-875 ◽  
Author(s):  
Hans-Helmut Paul ◽  
Helmut Sapper ◽  
Wolfgang Lohmann
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Binding Sites ◽  
Spectroscopic Data ◽  
Proton Magnetic Resonance ◽  
Proton Magnetic Resonance Spectroscopy ◽  
Bond Formation ◽  
Resonance Spectroscopy ◽  
Hydrogen Bond Formation ◽  
Dimer Model

The formation of hydrogen bonds between the minor tranquilizers diazepam and nitrazepam and a few nucleobases was studied in deuterochloroform solution by means of proton magnetic resonance spectroscopy. The thermodynamic and spectroscopic data of the associations were evaluated on the basis of a dimer model, using the concentration dependent shifts of the protons involved in hydrogen bonds. The interactions of nitrazepam (ΔH0= -10 to -21 k J/mol; ΔG250 - 0.2 to -7.4 kJ/mol) were found to be stronger than those of diazepam (ΔH0 = - 10 to - 13 kJ/mol; ΔG250 = 6.0 to 6.4 k j/mol). The various binding sites of the benzodiazepines for hydrogen bonds are discussed.

Different Structural States of the Proteolipid Membrane Are Produced by Ligand Binding to the Human δ-Opioid Receptor as Shown by Plasmon-Waveguide Resonance Spectroscopy

2004 ◽  
Vol 65 (5) ◽  
pp. 1248-1257 ◽  
Author(s):  
Isabel D. Alves ◽  
Scott M. Cowell ◽  
Zdzislaw Salamon ◽  
Savitha Devanathan ◽  
Gordon Tollin ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Opioid Receptor ◽  
Resonance Spectroscopy ◽  
Δ Opioid Receptor ◽  
Waveguide Resonance

scholarly journals Specificity of Escherichia coli Heat-Labile Enterotoxin Investigated by Single-Site Mutagenesis

2018 ◽  
Author(s):  
Julie E. Heggelund ◽  
Joel B. Heim ◽  
Gregor Bajc ◽  
Vesna Hodnik ◽  
Gregor Anderluh ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Binding Sites ◽  
Enterotoxigenic Escherichia Coli ◽  
Resonance Spectroscopy ◽  
Carbohydrate Binding ◽  
Heat Labile ◽  
Causes Of Mortality ◽  
Site Mutagenesis ◽  
Toxin Uptake ◽  
Great Burden

Diarrhoea caused by enterotoxigenic Escherichia coli is one of the leading causes of mortality in children under five years of age and is a great burden on developing countries. The major virulence factor of the bacterium is the heat-labile enterotoxin (LT), a close homologue of the cholera toxin. The toxins bind to carbohydrate receptors in the gastrointestinal tract, leading to toxin uptake and, ultimately, to severe diarrhoea. Previously, LT from human- and porcine-infecting ETEC (hLT and pLT, respectively) were shown to have different carbohydrate-binding specificities, in particular with respect to N-acetyllactosamine-terminating glycosphingolipids. Here, we probed eleven single-residue variants of the heat-labile enterotoxin with surface plasmon resonance spectroscopy and compared the data to the parent toxins. In addition we present a 1.45 Å crystal structure of pLTB in complex with branched Lacto-N-neohexaose (Galb4GlcNAcb6[Galb4GlcNAcb3]Galb4Glc). The largest difference in binding specificity is caused by mutation of residue 94, which links the primary and secondary binding sites of the toxins. Residue 95 (and to a smaller extent also residues 7 and 18) also contribute, whereas residue 4 shows no effect on monovalent binding of the ligand and may rather be important for multivalent binding, enhancing avidity.

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