Thermodynamics of ion binding to phosphatidic acid bilayers. Titration calorimetry of the heat of dissociation of DMPA

Biochemistry ◽  
1992 ◽  
Vol 31 (19) ◽  
pp. 4636-4642 ◽  
Author(s):  
A. Blume ◽  
J. Tuchtenhagen
Keyword(s):  
Phosphatidic Acid ◽  
Titration Calorimetry ◽  
Ion Binding ◽  
Heat Of Dissociation

The use of isothermal titration calorimetry to determine the thermodynamics of metal ion binding to low-cost sorbents

2010 ◽  
Vol 501 (1-2) ◽  
pp. 119-121 ◽  
Author(s):  
Vigdis Karlsen ◽  
Ellinor Bævre Heggset ◽  
Morten Sørlie
Keyword(s):  
Isothermal Titration Calorimetry ◽  
Metal Ion ◽  
Low Cost ◽  
Titration Calorimetry ◽  
Ion Binding ◽  
Metal Ion Binding

Ferrous Ion Binding to Recombinant Human H-Chain Ferritin. An Isothermal Titration Calorimetry Study†

Biochemistry ◽  
2002 ◽  
Vol 41 (37) ◽  
pp. 11184-11191 ◽  
Author(s):  
Fadi Bou-Abdallah ◽  
Paolo Arosio ◽  
Paolo Santambrogio ◽  
Xiaoke Yang ◽  
Christine Janus-Chandler ◽  
...  
Keyword(s):  
Isothermal Titration Calorimetry ◽  
Ferrous Ion ◽  
Titration Calorimetry ◽  
Ion Binding

scholarly journals Ion-binding properties of a K+ channel selectivity filter in different conformations

2015 ◽  
Vol 112 (49) ◽  
pp. 15096-15100 ◽  
Author(s):  
Shian Liu ◽  
Paul J. Focke ◽  
Kimberly Matulef ◽  
Xuelin Bian ◽  
Pierre Moënne-Loccoz ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Selectivity Filter ◽  
Titration Calorimetry ◽  
K Channel ◽  
Ion Binding ◽  
Binding Properties ◽  
Channel Opening ◽  
Channel Selectivity ◽  
Inactivation Process ◽  
Low K

K+ channels are membrane proteins that selectively conduct K+ ions across lipid bilayers. Many voltage-gated K+ (KV) channels contain two gates, one at the bundle crossing on the intracellular side of the membrane and another in the selectivity filter. The gate at the bundle crossing is responsible for channel opening in response to a voltage stimulus, whereas the gate at the selectivity filter is responsible for C-type inactivation. Together, these regions determine when the channel conducts ions. The K+ channel from Streptomyces lividians (KcsA) undergoes an inactivation process that is functionally similar to KV channels, which has led to its use as a practical system to study inactivation. Crystal structures of KcsA channels with an open intracellular gate revealed a selectivity filter in a constricted conformation similar to the structure observed in closed KcsA containing only Na+ or low [K+]. However, recent work using a semisynthetic channel that is unable to adopt a constricted filter but inactivates like WT channels challenges this idea. In this study, we measured the equilibrium ion-binding properties of channels with conductive, inactivated, and constricted filters using isothermal titration calorimetry (ITC). EPR spectroscopy was used to determine the state of the intracellular gate of the channel, which we found can depend on the presence or absence of a lipid bilayer. Overall, we discovered that K+ ion binding to channels with an inactivated or conductive selectivity filter is different from K+ ion binding to channels with a constricted filter, suggesting that the structures of these channels are different.

Corrigendum to: Phosphatidic acid binds to and regulates guanine nucleotide exchange factor 8 (GEF8) activity in Arabidopsis

2021 ◽  
Vol 48 (3) ◽  
pp. 359
Author(s):  
Chunyan Cao ◽  
Peipei Wang ◽  
Hongdi Song ◽  
Wen Jing ◽  
Like Shen ◽  
...  
Keyword(s):  
Phosphatidic Acid ◽  
Small Gtpase ◽  
Bimolecular Fluorescence Complementation ◽  
Titration Calorimetry ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Guanine Nucleotide Exchange ◽  
Synergistic Activation ◽  
Wide Range

Phosphatidic acid (PA) forms part of plant lipid metabolism and is a signalling molecule used in response to various external stresses. Guanine nucleotide exchange factors (GEFs) activate small GTPase ROPs, serving as molecular switches in a wide range of signalling pathways. However, the interaction between PA and GEFs in plants has not yet been reported. Here we show that PA bound specifically to GEF8 by using fat-Western blot and isothermal titration calorimetry assays. A C-terminal truncation of GEF8 exhibited strong PA binding, and mutation of lysines 13 and 18 in GEF8 PRONE domain caused a total loss of binding to PA. Two ROPs, ROP7 and ROP10, were identified as preferred substrates of GEF8 by pull-down and bimolecular fluorescence complementation assays. GEF8 activity towards ROP7, but not ROP10, was stimulated by PA both in vitro and in cells. Moreover, the PA- or ABA-induced activation of GEF8 was completely lost in the mutant GEF8, which did not bind to PA. Together, these findings identify a direct interconnection between PA-mediated GEFs activity and small GTPase signalling in plants and provide evidence for a synergistic activation of GEF8 by direct PA-binding to its PRONE domain.

Phosphatidic acid binds to and regulates guanine nucleotide exchange factor 8 (GEF8) activity in Arabidopsis

2017 ◽  
Vol 44 (10) ◽  
pp. 1029 ◽  
Author(s):  
Chunyan Cao ◽  
Peipei Wang ◽  
Hongdi Song ◽  
Wen Jing ◽  
Like Shen ◽  
...  
Keyword(s):  
Phosphatidic Acid ◽  
Small Gtpase ◽  
Bimolecular Fluorescence Complementation ◽  
Titration Calorimetry ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Guanine Nucleotide Exchange ◽  
Synergistic Activation ◽  
Wide Range

Phosphatidic acid (PA) forms part of plant lipid metabolism and is a signalling molecule used in response to various external stresses. Guanine nucleotide exchange factors (GEFs) activate small GTPase ROPs, serving as molecular switches in a wide range of signalling pathways. However, the interaction between PA and GEFs in plants has not yet been reported. Here we show that PA bound specifically to GEF8 by using fat-Western blot and isothermal titration calorimetry assays. A C-terminal truncation of GEF8 exhibited strong PA binding, and mutation of lysines 13 and 18 in GEF8 PRONE domain caused a total loss of binding to PA. Two ROPs, ROP7 and ROP10, were identified as preferred substrates of GEF8 by pull-down and bimolecular fluorescence complementation assays. GEF8 activity towards ROP7, but not ROP10, was stimulated by PA both in vitro and in cells. Moreover, the PA- or ABA-induced activation of GEF8 was completely lost in the mutant GEF8, which did not bind to PA. Together, these findings identify a direct interconnection between PA-mediated GEFs activity and small GTPase signalling in plants and provide evidence for a synergistic activation of GEF8 by direct PA-binding to its PRONE domain.

Cyclic phosphatidic acid (cPA)

2010 ◽  
Author(s):  
Emma Leah
Keyword(s):  
Phosphatidic Acid ◽  
Cyclic Phosphatidic Acid
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