Palmitoylation-Induced Conformational Changes of Specific Side Chains in the Gramicidin Transmembrane Channel

Biochemistry ◽  
1995 ◽  
Vol 34 (29) ◽  
pp. 9299-9306 ◽  
Author(s):  
Roger E. Koeppe ◽  
J. Antoinette Killian ◽  
T. C. Bas Vogt ◽  
Ben de Kruijff ◽  
M. Jeffrey Taylor ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Side Chains ◽  
Transmembrane Channel

Infrared spectra of N-acetyl-L-α-amino-acid N'-methylamides with aliphatic side chains in non-polar solvents

1981 ◽  
Vol 46 (3) ◽  
pp. 772-780 ◽  
Author(s):  
Jorga Smolíková ◽  
Jan Pospíšek ◽  
Karel Bláha
Keyword(s):  
Amino Acid ◽  
Conformational Changes ◽  
Infrared Spectra ◽  
Room Temperature ◽  
Side Chains ◽  
Polar Solvents

Infrared spectra of the L-alanine (I), L-leucine (II), L-valine (III) and L-tert-leucine (IV) N-acetyl N'-methylamides were measured. Amides I-IV are not self associated in tetrachlormethane in the concentration 2 . 10-5 mol l-1 at room temperature and in tetrachloroethylene in the concentration 1.5 . 10-4 mol l-1 at temperatures above 65° C. True conformational changes are observable only with the least flexible amide IV which exists at room temperature in a C5 conformation. This conformational type is also highly populated in the valine derivative III, but is less important in the alanine and leucine derivatives I and II in which the intramolecularly bonded C7 and the distorted hydrogen-nonbonded conformations contribute seriously.

Photoinduced conformational changes of azoaromatic polyaspartates containing octadecyl side chains

1990 ◽  
Vol 28 (5) ◽  
pp. 1161-1170 ◽  
Author(s):  
Akihiko Ueno ◽  
Kayo Adachi ◽  
Junko Nakamura ◽  
Tetsuo Osa
Keyword(s):  
Conformational Changes ◽  
Side Chains

The Mobility of Tryptophan and Dansyl Fluorophores in Labelled Poly(N-ethylacrylamide) and Poly(N-ethylmethacrylamide)

1993 ◽  
Vol 58 (10) ◽  
pp. 2383-2395 ◽  
Author(s):  
František Mikeš ◽  
Drahomír Výprachtický ◽  
Jan Pecka
Keyword(s):  
Conformational Changes ◽  
High Viscosity ◽  
Side Chains ◽  
Fluorescence Depolarization ◽  
Polymer Backbone ◽  
Short Side ◽  
Low Viscosity ◽  
Viscosity Range ◽  
Methylene Groups ◽  
Intramolecular Association

The mobility of tryptophan fluorophore in N-butyl-Nα-acetyltryptophanamide and in side chain of labelled poly(N-ethylacrylamide) and poly(N-ethylmethacrylamide) was investigated by the fluorescence depolarization method. The mobility of the fluorophore in the low-molecular-weight model is much higher than in side chains of the polymers. Different steric hindrance by the polymer backbone can explain the higher mobility of the fluorophore in poly(N-ethylacrylamide) and in poly(N-ethylmethacrylamide). The mobility of 5-dimethylamino-1-naphthalenesulfonamide (dansyl) fluorophore in side chains of labelled poly(N-ethylmethacrylamide) in the high-viscosity range increases with increasing number of methylene groups in side chains. The low-viscosity range, the rate s of conformational changes in short side chains (n = 2 - 7) are approximately constant and significantly decrease in long side chains (n = 10, 12). The drop in the rates is probably due to intramolecular association of the long hydrophobic chains in water.

Light-induced conformational changes in chiral polymers with photochromic side chains

1984 ◽  
Vol 56 (3) ◽  
pp. 329-342 ◽  
Author(s):  
F. Ciardelli ◽  
C. Carlini ◽  
R. Solaro ◽  
Angelina Altomare ◽  
O. Pieroni ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Side Chains ◽  
Chiral Polymers

scholarly journals Mechanical gating of the auditory transduction channel TMC1 involves the fourth and sixth transmembrane helices

2022 ◽  
Author(s):  
Nurunisa Akyuz ◽  
K. Domenica Karavitaki ◽  
Bifeng Pan ◽  
Panos I. Tamvakologos ◽  
Kelly P. Brock ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Hair Cells ◽  
Single Channel ◽  
Transmembrane Helices ◽  
Open Probability ◽  
Transmembrane Channel ◽  
Force Sensitivity ◽  
Electrophysiological Recordings ◽  
Auditory Transduction ◽  
Pore Lining

The transmembrane channel-like (TMC) 1 and 2 proteins play a central role in auditory transduction, forming ion channels that convert sound into electrical signals. However, the molecular mechanism of their gating remains unknown. Here, using predicted structural models as a guide, we probed the effects of twelve mutations on the mechanical gating of the transduction currents in native hair cells of Tmc1/2-null mice expressing virally introduced TMC1 variants. Whole-cell electrophysiological recordings revealed that mutations within the pore-lining transmembrane (TM) helices 4 and 6 modified gating, reducing the force sensitivity or shifting the open probability of the channels, or both. For some of the mutants, these changes were accompanied by a change in single-channel conductance. Our observations are in line with a model wherein conformational changes in the TM4 and TM6 helices are involved in the mechanical gating of the transduction channel.

Reversible conformational changes induced by light in poly(L-glutamic acid) with photochromic side chains

1980 ◽  
Vol 102 (18) ◽  
pp. 5913-5915 ◽  
Author(s):  
Osvaldo Pieroni ◽  
Julien L. Houben ◽  
Adriano Fissi ◽  
Paolo Costantino ◽  
Francesco Ciardelli
Keyword(s):  
Glutamic Acid ◽  
Conformational Changes ◽  
Side Chains

scholarly journals Cadmium opens GluK2 kainate receptors with cysteine substitutions at the M3 helix bundle crossing

2018 ◽  
Vol 151 (4) ◽  
pp. 435-451 ◽  
Author(s):  
Timothy J. Wilding ◽  
James E. Huettner
Keyword(s):  
Conformational Changes ◽  
Site Occupancy ◽  
Kainate Receptors ◽  
Inhibitory Synapses ◽  
Side Chains ◽  
Glutamatergic Synapses ◽  
Channel Opening ◽  
The Central Nervous System ◽  
Excitatory Neurotransmission ◽  
Ion Pore

Kainate receptors are ligand-gated ion channels that have two major roles in the central nervous system: they mediate a postsynaptic component of excitatory neurotransmission at some glutamatergic synapses and modulate transmitter release at both excitatory and inhibitory synapses. Accumulating evidence implicates kainate receptors in a variety of neuropathologies, including epilepsy, psychiatric disorders, developmental delay, and cognitive impairment. Here, to gain a deeper understanding of the conformational changes associated with agonist binding and channel opening, we generate a series of Cys substitutions in the GluK2 kainate receptor subunit, focusing on the M3 helices that line the ion pore and form the bundle-crossing gate at the extracellular mouth of the channel. Exposure to 50 µM Cd produces direct activation of homomeric mutant channels bearing Cys substitutions in (A657C), or adjacent to (L659C), the conserved SYTANLAAF motif. Activation by Cd is occluded by modification with 2-aminoethyl MTS (MTSEA), indicating that Cd binds directly and specifically to the substituted cysteines. Cd potency for the A657C mutation (EC50 = 10 µM) suggests that binding involves at least two coordinating residues, whereas weaker Cd potency for L659C (EC50 = 2 mM) implies that activation does not require tight coordination by multiple side chains for this substitution. Experiments with heteromeric and chimeric channels indicate that activation by Cd requires Cys substitution at only two of the four subunits within a tetrameric receptor and that activation is similar for substitution within subunits in either the A/C or B/D conformations. We develop simple kinetic models for the A657C substitution that reproduce several features of Cd activation as well as the low-affinity inhibition observed at higher Cd concentrations (5–20 mM). Together, these results demonstrate rapid and reversible channel activation, independent of agonist site occupancy, upon Cd binding to Cys side chains at two specific locations along the GluK2 inner helix.

Transverse13C Relaxation of CHD2Methyl Isotopmers To Detect Slow Conformational Changes of Protein Side Chains

1999 ◽  
Vol 121 (49) ◽  
pp. 11589-11590 ◽  
Author(s):  
Rieko Ishima ◽  
John M. Louis ◽  
Dennis A. Torchia
Keyword(s):  
Conformational Changes ◽  
Side Chains
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