Azo‐hydrazone molecular switches: Synthesis and NMR conformational investigation

2021 ◽  
Author(s):  
Atanas Kurutos ◽  
Fadhil S. Kamounah ◽  
Georgi M. Dobrikov ◽  
Michael Pittelkow ◽  
Stephan P. A. Sauer ◽  
...  
Keyword(s):  
Molecular Switches ◽  
Conformational Investigation

Synthesis and conformational investigation of β-turn forming tetra- and hexapeptides

1982 ◽  
Vol 47 (7) ◽  
pp. 1884-1892
Author(s):  
A. N. Abdel Rahman ◽  
S. Abdel Rahman
Keyword(s):  
Energy Transfer ◽  
Phase Method ◽  
Conformational Study ◽  
Poly Ethylene Glycol ◽  
High Solubility ◽  
Liquid Phase Method ◽  
Conformational Investigation ◽  
Transfer Method ◽  
Poly Ethylene ◽  
Good Agreement

Tetra- and hexapeptides containing Pro-Gly or Gly-Pro or Aib-Pro in their sequences were synthesized using the liquid-phase method. The high solubility of the poly(ethylene glycol) bound peptides in water and in organic solvents enables the application of the singlet-singlet energy transfer method for conformational investigation of these peptides. The conformational study in solid state by IR and in solution by CD were carried out in parallel to the energy transfer method. The qualitative results generated by IR and CD were found to be in good agreement with the quantitative end-to-end distances given by the energy transfer method.

Protein tyrosine phosphatases: molecular switches in metabolism and diabetes

2015 ◽  
Vol 26 (1) ◽  
pp. 30-39 ◽  
Author(s):  
Esteban N. Gurzov ◽  
William J. Stanley ◽  
Thomas C. Brodnicki ◽  
Helen E. Thomas
Keyword(s):  
Protein Tyrosine Phosphatases ◽  
Molecular Switches ◽  
Tyrosine Phosphatases ◽  
Protein Tyrosine

Metal ions doped into merocyanine form of coumarin derivatives: nonlinear optical molecular switches

2019 ◽  
Vol 25 (8) ◽  
Author(s):  
Ali Muhammad Arif ◽  
Afifa Yousaf ◽  
Rong-Lin Zhong ◽  
Mansoor Akhtar ◽  
Shabbir Muhammad ◽  
...  
Keyword(s):  
Metal Ions ◽  
Nonlinear Optical ◽  
Molecular Switches ◽  
Merocyanine Form ◽  
Coumarin Derivatives

scholarly journals Pore-forming Esx proteins mediate toxin secretion by Mycobacterium tuberculosis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Uday Tak ◽  
Terje Dokland ◽  
Michael Niederweis
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Pore Formation ◽  
Molecular Switches ◽  
Water Soluble ◽  
Host Cells ◽  
Solvent Exposure ◽  
Membrane Channel ◽  
Toxin Secretion ◽  
Outer Membrane Channel ◽  
Membrane Spanning

AbstractMycobacterium tuberculosis secretes the tuberculosis necrotizing toxin (TNT) to kill host cells. Here, we show that the WXG100 proteins EsxE and EsxF are essential for TNT secretion. EsxE and EsxF form a water-soluble heterodimer (EsxEF) that assembles into oligomers and long filaments, binds to membranes, and forms stable membrane-spanning channels. Electron microscopy of EsxEF reveals mainly pentameric structures with a central pore. Mutations of both WXG motifs and of a GXW motif do not affect dimerization, but abolish pore formation, membrane deformation and TNT secretion. The WXG/GXW mutants are locked in conformations with altered thermostability and solvent exposure, indicating that the WXG/GXW motifs are molecular switches controlling membrane interaction and pore formation. EsxF is accessible on the bacterial cell surface, suggesting that EsxEF form an outer membrane channel for toxin export. Thus, our study reveals a protein secretion mechanism in bacteria that relies on pore formation by small WXG proteins.

scholarly journals PAK and other Rho-associated kinases – effectors with surprisingly diverse mechanisms of regulation

2005 ◽  
Vol 386 (2) ◽  
pp. 201-214 ◽  
Author(s):  
Zhou-shen ZHAO ◽  
Ed MANSER
Keyword(s):  
Rho Gtpases ◽  
Cell Biology ◽  
Rho Gtpase ◽  
Rho Kinase ◽  
Molecular Switches ◽  
Eukaryotic Cell ◽  
Effector Proteins ◽  
Downstream Effector ◽  
P21 Activated Kinase ◽  
Do So

The Rho GTPases are a family of molecular switches that are critical regulators of signal transduction pathways in eukaryotic cells. They are known principally for their role in regulating the cytoskeleton, and do so by recruiting a variety of downstream effector proteins. Kinases form an important class of Rho effector, and part of the biological complexity brought about by switching on a single GTPase results from downstream phosphorylation cascades. Here we focus on our current understanding of the way in which different Rho-associated serine/threonine kinases, denoted PAK (p21-activated kinase), MLK (mixed-lineage kinase), ROK (Rho-kinase), MRCK (myotonin-related Cdc42-binding kinase), CRIK (citron kinase) and PKN (protein kinase novel), interact with and are regulated by their partner GTPases. All of these kinases have in common an ability to dimerize, and in most cases interact with a variety of other proteins that are important for their function. A diversity of known structures underpin the Rho GTPase–kinase interaction, but only in the case of PAK do we have a good molecular understanding of kinase regulation. The ability of Rho GTPases to co-ordinate spatial and temporal phosphorylation events explains in part their prominent role in eukaryotic cell biology.

A complete structural and conformational investigation of procyanidin A2 dimer

1996 ◽  
Vol 37 (12) ◽  
pp. 2015-2018 ◽  
Author(s):  
Nicolas Vivas ◽  
Yves Glories ◽  
Isabelle Pianet ◽  
Bernard Barbe ◽  
Michel Laguerre
Keyword(s):  
Conformational Investigation

Cellulose organic solvents: V. Conformational aspects of N,N-dimethyl ethanolamine N-oxide in its crystalline and diluted states

1984 ◽  
Vol 62 (1) ◽  
pp. 6-10 ◽  
Author(s):  
E. R. Maia ◽  
A. Péguy ◽  
S. Pérez
Keyword(s):  
Tertiary Amine ◽  
Amine Oxide ◽  
Direct Methods ◽  
Monoclinic Space Group ◽  
Cyclic Form ◽  
Asymmetric Unit ◽  
Ir And Nmr Spectroscopy ◽  
Conformational Investigation ◽  
Intramolecular Hydrogen ◽  
Strong Intramolecular Hydrogen Bond

N,N-Dimethyl ethanolamine N-oxide (DMEAO) belongs to the class of tertiary amine oxide molecules that are good solvents for cellulose, although not being cyclic. Crystallographic investigation shows that anhydrous DMEAO is monoclinic, space group Cc, a = 25.725(9), b = 7.023(4), c = 9.483(5) Å, β = 101.16(10)°, Z = 12. The crystal structure has been solved by direct methods and refined to a final R value of 0.063 for 575 observed reflexions. Three independent molecules are found within the asymmetric unit; one of these displays a pseudo-cyclic form dictated by the occurrence of a strong intramolecular hydrogen bond. Conformational investigation of DMEAO in solution, using ir and nmr spectroscopy shows that this pseudo-cyclic form is more likely to occur in diluted states. These findings are related to the ability of this tertiary amine oxide to act as a good solvent, up to a water content of one water molecule per DMEAO molecule.

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