scholarly journals Thrombin-thrombomodulin interaction: energetics and potential role of water as an allosteric effector

1995 ◽  
Vol 310 (1) ◽  
pp. 49-53 ◽  
Author(s):  
R De Cristofaro ◽  
M Picozzi ◽  
E De Candia ◽  
B Rocca ◽  
R Landolfi
Keyword(s):  
Conformational Changes ◽  
Potential Role ◽  
Competitive Inhibition ◽  
Entropy Change ◽  
Bulk Water ◽  
Water Molecules ◽  
Rabbit Lung ◽  
Allosteric Effector ◽  
Free Energy Of Binding

The interaction of rabbit lung thrombomodulin (TM) and C-terminal hirudin 54-65 fragment (Hir54-65) with human alpha-thrombin were investigated by exploiting their competitive inhibition of thrombin-fibrinogen interaction. Measurements of Ki values for TM and Hir54-65 interactions with human alpha-thrombin performed over a temperature range spanning from 10 to 40 degrees C showed a constant enthalpy for both ligands. The enthalpic and entropic contributions to the free energy of binding, however, are different for TM and the hirudin peptide. The calculated values of delta H and delta S, in fact, were -47.3 +/- 2.51 kJ (-11.3 +/- 0.6 kcal)/mol and -42.7 +/- 7.9 J (-10.2 +/- 1.9 cal)/mol.K for the hirudin peptide, while being -22.9 +/- 2.09 kJ (-5.47 +/- 0.5 kcal)/mol and 102.50 +/- 6.69 J (24.5 +/- 1.6 cal)/mol.K respectively for TM binding. These findings indicate that the interaction between thrombin and Hir54-65 is largely driven by the enthalpic contribution, whereas the positive entropy change is the driving force for the formation of the thrombin-TM complex. In other experiments performed in the presence of various concentrations of either sorbitol or sucrose it could be demonstrated that the value of the equilibrium association constant for thrombin-TM interaction increases as a function of the osmotic pressure, while the thrombin-Hir54-65 interaction was not affected by the same conditions. Moreover, control experiments showed that no major conformational changes are produced on TM by osmotic pressures used in the present study. From these experiments it was calculated that roughly 35 water molecules are released into the bulk water upon TM binding. Such a phenomenon, which is likely to be responsible for the entropic change described above, indicates the relevance of hydration processes for the formation of the thrombin-TM adduct.

scholarly journals The role of water and protein flexibility in the structure-based virtual screening of allosteric GPCR modulators: an mGlu5 receptor case study

2019 ◽  
Vol 33 (9) ◽  
pp. 787-797 ◽  
Author(s):  
Zoltán Orgován ◽  
György G. Ferenczy ◽  
György M. Keserű
Keyword(s):  
Virtual Screening ◽  
Ligand Binding ◽  
Conformational Changes ◽  
Metabotropic Glutamate Receptor ◽  
Protein Structures ◽  
Protein Flexibility ◽  
Water Molecules ◽  
Large Set ◽  
Allosteric Modulators

Abstract Stabilizing unique receptor conformations, allosteric modulators of G-protein coupled receptors (GPCRs) might open novel treatment options due to their new pharmacological action, their enhanced specificity and selectivity in both binding and signaling. Ligand binding occurs at intrahelical allosteric sites and involves significant induced fit effects that include conformational changes in the local protein environment and water networks. Based on the analysis of available crystal structures of metabotropic glutamate receptor 5 (mGlu5) we investigated these effects in the binding of mGlu5 receptor negative allosteric modulators. A large set of retrospective virtual screens revealed that the use of multiple protein structures and the inclusion of selected water molecules improves virtual screening performance compared to conventional docking strategies. The role of water molecules and protein flexibility in ligand binding can be taken into account efficiently by the proposed docking protocol that provided reasonable enrichment of true positives. This protocol is expected to be useful also for identifying intrahelical allosteric modulators for other GPCR targets.

scholarly journals The three-dimensional structure of a class-Pi glutathione S-transferase complexed with glutathione: the active-site hydration provides insights into the reaction mechanism

1998 ◽  
Vol 333 (3) ◽  
pp. 811-816 ◽  
Author(s):  
Antonio PÁRRAGA ◽  
Isabel GARCÍA-SÁEZ ◽  
Sinead B. WALSH ◽  
Timothy J. MANTLE ◽  
Miquel COLL
Keyword(s):  
Conformational Changes ◽  
Active Site ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Glutathione S Transferase ◽  
X Ray ◽  
The Right

The structure of mouse liver glutathione S-transferase P1-1 complexed with its substrate glutathione (GSH) has been determined by X-ray diffraction analysis. No conformational changes in the glutathione moiety or in the protein, other than small adjustments of some side chains, are observed when compared with glutathione adduct complexes. Our structure confirms that the role of Tyr-7 is to stabilize the thiolate by hydrogen bonding and to position it in the right orientation. A comparison of the enzyme–GSH structure reported here with previously described structures reveals rearrangements in a well-defined network of water molecules in the active site. One of these water molecules (W0), identified in the unliganded enzyme (carboxymethylated at Cys-47), is displaced by the binding of GSH, and a further water molecule (W4) is displaced following the binding of the electrophilic substrate and the formation of the glutathione conjugate. The possibility that one of these water molecules participates in the proton abstraction from the glutathione thiol is discussed.

scholarly journals Intriguing Role of Water in Plant Hormone Perception

2021 ◽  
Author(s):  
Chuankai Zhao ◽  
Diego Eduardo Kleiman ◽  
Diwakar Shukla
Keyword(s):  
Free Energy ◽  
Plant Growth ◽  
Binding Site ◽  
Plant Hormones ◽  
Plant Hormone ◽  
Water Molecules ◽  
Water Displacement ◽  
Dynamics Simulations ◽  
Free Energy Of Binding

Plant hormones are small molecules that regulate plant growth, development, and responses to biotic and abiotic stresses. Plant hormones are specifically recognized by the binding site of their receptors. In this work, we investigated the role of water displacement and reorganization at the binding site of plant receptors on the binding of eight classes of phytohormones (auxin, jasmonate, gibberellin, strigolactone, brassinosteroid, cytokinin, salicylic acid, and abscisic acid) using extensive molecular dynamics simulations and inhomogeneous solvation theory. Our findings demonstrated that displacement of water molecules by phytohormones contributes to free energy of binding via entropy gain and is associated with free energy barriers. Also, our results have shown that displacement of unfavorable water molecules in the binding site can be exploited in rational agrochemical design. Overall, this study uncov- ers the role of water molecules in plant hormone perception, which creates new avenues for agrochemical design to target plant growth and development.

scholarly journals Non-ionotropic signaling by the NMDA receptor: controversy and opportunity

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 1010 ◽  
Author(s):  
John A. Gray ◽  
Karen Zito ◽  
Johannes W. Hell
Keyword(s):  
Nmda Receptor ◽  
Conformational Changes ◽  
Potential Role ◽  
Calcium Influx ◽  
Receptor Signaling ◽  
Long Term Depression ◽  
New Era ◽  
Channel Opening

Provocative emerging evidence suggests that the N-methyl-D-aspartate (NMDA) receptor can signal in the absence of ion flux through the receptor. This non-ionotropic signaling is thought to be due to agonist-induced conformational changes in the receptor, independently of channel opening. Non-ionotropic NMDA receptor signaling has been proposed to be sufficient to induce synaptic long-term depression (LTD), directly challenging the decades-old model that prolonged low-level calcium influx is required to induce LTD. Here, we briefly review these recent findings, focusing primarily on the potential role of non-ionotropic signaling in NMDA receptor-mediated LTD. Further reports concerning additional roles of non-ionotropic NMDA receptor signaling are also discussed. If validated, this new view of NMDA receptor-mediated signaling will usher in an exciting new era of exploring synapse function and dysfunction.

scholarly journals The role of water molecules in the binding of class I and II peptides to the SH3 domain of the Fyn tyrosine kinase

2016 ◽  
Vol 72 (9) ◽  
pp. 707-712 ◽  
Author(s):  
Ana Camara-Artigas ◽  
Emilia Ortiz-Salmeron ◽  
Montserrrat Andujar-Sánchez ◽  
Julio Bacarizo ◽  
Jose Manuel Martin-Garcia
Keyword(s):  
Tyrosine Kinase ◽  
Conformational Changes ◽  
Sh3 Domain ◽  
Class I ◽  
Water Molecules ◽  
Src Tyrosine Kinase ◽  
Sh3 Domains ◽  
Binding Interface ◽  
Fyn Tyrosine Kinase

Interactions of proline-rich motifs with SH3 domains are present in signal transduction and other important cell processes. Analysis of structural and thermodynamic data suggest a relevant role of water molecules in these protein–protein interactions. To determine whether or not the SH3 domain of the Fyn tyrosine kinase shows the same behaviour, the crystal structures of its complexes with two high-affinity synthetic peptides, VSL12 and APP12, which are class I and II peptides, respectively, have been solved. In the class I complexes two water molecules were found at the binding interface that were not present in the class II complexes. The structures suggest a role of these water molecules in facilitating conformational changes in the SH3 domain to allow the binding of the class I or II peptides. In the third binding pocket these changes modify the cation–π and salt-bridge interactions that determine the affinity of the binding. Comparison of the water molecules involved in the binding of the peptides with previous reported hydration spots suggests a different pattern for the SH3 domains of the Src tyrosine kinase family.

scholarly journals Brillouin Neutron Spectroscopy as a Probe to Investigate Collective Density Fluctuations in Biomolecules Hydration Water

2012 ◽  
Vol 27 ◽  
pp. 293-305 ◽  
Author(s):  
D. Russo ◽  
A. Orecchini ◽  
A. De Francesco ◽  
F. Formisano ◽  
A. Laloni ◽  
...  
Keyword(s):  
Diffusion Processes ◽  
Terahertz Spectroscopy ◽  
Bulk Water ◽  
Density Fluctuations ◽  
Water Molecules ◽  
Relaxation Processes ◽  
Hydration Water ◽  
Solvent Interaction ◽  
Biological Functionality

The role of water in the behaviour of biomolecules is well recognized. The coupling of motions between water and biomolecules has been studied in a wide time scale for theselfpart whilecollectivedynamics is still quite unexplored.Self-dynamics provides information about the diffusion processes of water molecules and relaxation processes of the protein structure.Collectivedensity fluctuations might provide important insight on the transmission of information possibly correlated to biological functionality. The idea that hydration water layers surrounding a biological molecule show aself-dynamical signature that differs appreciably from that of bulk water, in analogy with glass-former systems, is quite accepted. In the same picture Brillouin terahertz spectroscopy has been used to directly probecollectivedynamics of hydration water molecules around biosystems, showing a weaker coupling and a more bulklike behaviour. We will discuss results of collective modes of hydration water, arising from neutron Brillouin spectroscopy, in the context of biomolecules-solvent interaction.

Role of spectrin in membrane fusion and in shape change of human erythrocyte ghost

1978 ◽  
Vol 36 (2) ◽  
pp. 328-329
Author(s):  
Hideo Hayashi ◽  
Yoshikazu Hirai ◽  
John T. Penniston
Keyword(s):  
Conformational Changes ◽  
Human Erythrocyte ◽  
Shape Change ◽  
Membrane Surface ◽  
Slight Modification ◽  
Active Role ◽  
Main Role ◽  
Bank Blood ◽  
Human Erythrocyte Ghost

Spectrin is a membrane associated protein most of which properties have been tentatively elucidated. A main role of the protein has been assumed to give a supporting structure to inside of the membrane. As reported previously, however, the isolated spectrin molecule underwent self assemble to form such as fibrous, meshwork, dispersed or aggregated arrangements depending upon the buffer suspended and was suggested to play an active role in the membrane conformational changes. In this study, the role of spectrin and actin was examined in terms of the molecular arrangements on the erythrocyte membrane surface with correlation to the functional states of the ghosts.Human erythrocyte ghosts were prepared from either freshly drawn or stocked bank blood by the method of Dodge et al with a slight modification as described before. Anti-spectrin antibody was raised against rabbit by injection of purified spectrin and partially purified.

POPDC proteins and cardiac function

2019 ◽  
Vol 47 (5) ◽  
pp. 1393-1404 ◽  
Author(s):  
Thomas Brand
Keyword(s):  
Potential Role ◽  
Striated Muscle ◽  
Short Review ◽  
Effector Proteins ◽  
Muscle Disease ◽  
Disease Genes ◽  
Protein Protein Interaction ◽  
Interaction Partners ◽  
And Function

Abstract The Popeye domain-containing gene family encodes a novel class of cAMP effector proteins in striated muscle tissue. In this short review, we first introduce the protein family and discuss their structure and function with an emphasis on their role in cyclic AMP signalling. Another focus of this review is the recently discovered role of POPDC genes as striated muscle disease genes, which have been associated with cardiac arrhythmia and muscular dystrophy. The pathological phenotypes observed in patients will be compared with phenotypes present in null and knockin mutations in zebrafish and mouse. A number of protein–protein interaction partners have been discovered and the potential role of POPDC proteins to control the subcellular localization and function of these interacting proteins will be discussed. Finally, we outline several areas, where research is urgently needed.

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