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Topic: Random coil

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In the News (Tue 25 Jun 19)

  Tesla Coil Mailing List
The tesla coil mailing list that I run covers the topics of tesla coil construction, operation, measurement, and use.
The level of knowledge among the list members ranges from people who hardly know what a tesla coil is, to true professional tesla coil builders and professional physicists.
Tesla coil operation involves high energy electrical discharge, high voltages, and often high speed rotary gaps.
www.pupman.com   (325 words)

  Structure of the prion repeat region
As earlier studies reported a simple random coil structure for the repeat region, it is first necessary to recollect anomalous structural properties of proline generally, of periodic proline in the protein world, and the location and role of proline in the prion molecule.
-- The random coil found in nmr is then an artefact due to the presence of metal chelating agent and absence of prolyl isomerase; the correct state may be populated to some extent but is lost in averaging over all states.
Note that the repeat region has a random coil conformer, a stiff but extended coils in the absence of copper, and a compacter coil in the presence of copper.
www.mad-cow.org /~tom/prion_proline.html   (8188 words)

  Random coil
In random coil, the only fixed relationship between amino acids is that between adjacent residues through the peptide bond.
As a result, random coil can be detected from the absence of the signals in a multidimensional nuclear magnetic resonance experiment that depend on particular peptide-peptide interactions.
Random coil is also easily distinguished by circular dichroism.
www.wapipedia.com /wikipedia/mobiletopic.aspx?cur_title=Random_coil   (155 words)

 Coil   (Site not responding. Last check: )
An ''electromagnetic coil'' (or simply a "coil") is formed when a conductor (usually a solid copper wire) is wound around a core or form to create an inductor or electromagnet.
The coil tap(s) are points in a wire coil where a conductive patch has been exposed (usually on a loop of wire that extends out of the main coil body).
Multilayer coils have the problem of interlayer capacitance, so when multiple layers are needed the shape needs to be radically changed to a short coil with many layers so that the voltage between consecutive layers is smaller (making them more spiral like).
www.artistopia.com /coil   (1579 words)

 Random coil - Biocrawler   (Site not responding. Last check: )
A random coil is a polymer conformation where the monomers are arranged at random.
Proteins, segments of proteins, and peptides that lack secondary structure inhabit the random coil conformation.
In random coil, the only fixed relationship between amino acids is that between adjacent residues through the peptide bond.
www.biocrawler.com /encyclopedia/Random_coil   (386 words)

The random coil domain would be a volume of radius r centered on the surface of the b-tubulin sphere (which itself excludes a portion of the volume).
For example, release of the random coil domains should cause the pair of protofilaments that define the seam to slip.
Given this characteristic size of the random coil domain, it is possible to estimate the number of amino acids that comprise it from the radius of gyration of a self-avoiding random walk, r = N3/5a.
www.physics.ucsb.edu /~deborah/res/res_2.htm   (841 words)

 News | TimesDaily.com | TimesDaily | Florence, Alabama (AL)   (Site not responding. Last check: )
Below their melting temperatures, most thermoplastic polymers (polyethylene, nylon, etc.) have amorphous regions in which the chains approximate random coils, alternating with regions which are crystalline.
But segments of proteins, and polypeptides that lack secondary structure, are often assumed to exhibit a random coil conformation in which the only fixed relationship is the joining of adjacent amino acid residues by a peptide bond.
The conformational entropy associated with the random coil state significantly contributes to its energetic stabilization and accounts for much of the energy barrier to protein folding.
www.timesdaily.com /apps/pbcs.dll/section?category=NEWS&template=wiki&text=random_coil   (1277 words)

 Random coil   (Site not responding. Last check: )
In biochemistry, the random coil is a secondary structural motif seen in proteins, in which the distances between amino acids is fixed only by the peptide bond that connects them.
Proteins in a random coil configuration have a distinct ultraviolet circular dichroism signal associated with them, and can be identifed this way as well.
Proteins whose secondary structure has been reduced to pure random coil are said to be denatured.
www.usapedia.com /r/random-coil.html   (168 words)

 CiteULike: Reassessing random-coil statistics in unfolded proteins   (Site not responding. Last check: )
The Gaussian-distributed random coil has been the dominant model for denatured proteins since the 1950s, and it has long been interpreted to mean that proteins are featureless, statistical coils in 6 M guanidinium chloride.
Specifically, proteins of known structure were used to generate disordered conformers by varying backbone torsion angles at random for approx8% of the residues; the remaining approx92% of the residues remained fixed in their native conformation.
@article{citeulike:411234, abstract = {The Gaussian-distributed random coil has been the dominant model for denatured proteins since the 1950s, and it has long been interpreted to mean that proteins are featureless, statistical coils in 6 M guanidinium chloride.
www.citeulike.org /user/apaydin/article/411234   (403 words)

 Random coil: Encyclopedia II - Random coil - Real polymers
Unlike the zero volume assumed in a random walk calculation, all real polymers' segments occupy space because of the van der Waals radii of their atoms, including bulky substituent groups which interfere with bond rotations.
Even with corrections for local constraints, the random walk model ignores steric interference between chains, and between distal parts of the same chain.
A chain often can’t move from a given conformation to a closely related one by a small displacement because one part of it would have to pass through another part, or through a neighbor.
www.experiencefestival.com /a/Random_coil_-_Real_polymers/id/5408433   (590 words)

At extreme pH conditions, there were changes in intensity in bands attributed to beta-sheet (1637 and 1618 cm(-1)) and random coil (1644 cm(-1)) structures, and shifts of these bands to lower or higher wave numbers, indicating changes in protein conformation.
Chaotropic salts caused progressive increases in random coil structures and concomitant decreases in beta-sheet bands, following the lyotrophic series of anions.
In the presence of sodium dodecyl sulfate and ethylene glycol, pronounced increases in the random coil band were observed, accompanied by slight shifts of the beta-sheet band.
cmbi.bjmu.edu.cn /ChinaPaper/details.asp?PubMedID=11718826   (244 words)

 Random coil
Proteins, segments of proteins, and peptides that lack secondary structure inhabit the random coil conformation.
The random coil conformation can be detected using spectroscopic techniques.
the polymer as a freely jointed chain, one can look at each chain as doing random walk or more accurately constrained random walk and it can be shown that number of polymers with a any distance l between the ends of the chain will follow a normal distribution.
www.uk.kunsimuna.net /Random_coil_UK_640466_em   (492 words)

 Unit 12
Two samples are taken from each of two reproducible locations in each coil: the "head" (outside of the coil) and the "tail" (inside, where the curvature is greatest).
Coil is a random effect, nested within Annealing methods.
Random differences among Coils within Annealing methods are an important source of variability (presumably as anticipated in formulating the model).
www.sci.csuhayward.edu /~btrumbo/Stat3503/u12.htm   (1327 words)

 Other Nonrepetitive Structure: The Anatomy & Taxonomy of Protein Structure
Sometimes coil is referred to as "random coil," or is modeled by properties observed in 6M guanidine hydrochloride.
This seems unfortunate, since the actual portions of crystallographically determined protein structures generally described as coil are not random or disordered in any sense of the word; they are every bit as highly organized and firmly held in place as the repeating secondary structures — they are simply harder to describe.
A few instances have so far been described in which a particular organization of coil structure can be recognized as providing a particular type of functional site, since it occurs with very similar patterns in more than one example.
kinemage.biochem.duke.edu /~jsr/html/anatax.2f.html   (1093 words)

 GROMACS: Fast, Free and Flexible MD
CD spectra showed that, at 75% v/v methanol, the transition from random coil to fully helical structure was obtained, in a pH 1.1 HCl solution in the presence of 20 mm NaCl.
As the charge of the polypeptide (a pure polycation at a pH of 2.1 in CZE) was kept rigorously constant, a plot of the radius of the polymer along the sigmoidal transition clearly showed that the radius of gyration of the helical, structured polypeptide was in fact larger than that of the random coil.
Such results were confirmed by molecular dynamics simulations, which indicated that the dimensions of such polypeptide, in alpha-helix configuration, were 8.5 nm (in length) and 3.2 nm (in diameter), whereas those of the corresponding random coil were 7.2 nm (in length) and 5.1 nm (length of shorter axis).
www.gromacs.org /index.php?option=com_docgallery&Itemid=181&func=detail&id=266   (278 words)

 Rubbers and Elastomers - An Introduction
In this process the random coils are tied or cross-linked to others at intervals randomly along their length.
Crystallisation involves segments of a random coil coming into close proximity to a neighbouring coil allowing areas of high organisation (crystallites) to form within the bulk.
It is not possible particularly with cross-linked polymers, for the whole mass to be crystalline and a ‘percentage crystallinity’ figure is used to describe the condition, which varies with polymer structure, level of orientation, and temperature.
www.azom.com /details.asp?ArticleID=317   (1552 words)

 Sandwalk: How Proteins Fold
Within seconds, this random coil spontaneously folds itself into a highly ordered three-dimensional structure such that every single molecule of a given protein has the exact same shape.
The final structure of a protein minimizes the energy of the random coil by burying hydrophobic amino acids in the interior of the molecule.
Since 'change of gene frequencies in populations' is the 'official' definition of evolution, randomness has transgressed Darwin's border and asserted itself as an agent of evolutionary change.
sandwalk.blogspot.com /2007/02/how-proteins-fold.html   (2074 words)

 Spartanburg SC | GoUpstate.com | Spartanburg Herald-Journal   (Site not responding. Last check: )
This protein was the first to have its structure resolved by X-ray crystallography by Max Perutz and Sir John Cowdery Kendrew in 1958, which led to them receiving a Nobel Prize in Chemistry in 1962.
The random coil is not a true secondary structure, but is the class of conformations that indicate an absence of regular secondary structure.
A significant increase in accuracy (to nearly ~80%) was made by exploiting multiple sequence alignment; knowing the full distribution of amino acids that occur at a position (and in its vicinity, typically ~7 residues on either side) throughout evolution provides a much better picture of the structural tendencies near that position.
www.goupstate.com /apps/pbcs.dll/section?category=NEWS&template=wiki&text=secondary_structure   (1855 words)

 Definition of Random coil
A random coil is a polymer conformation where the monomers are arranged at random.
Deviations from these values often indicates the presence of secondary structure and thus the absence of random coil.
Furthermore, signals in multidimensional NMR experiment that indicate stable, non-local amino acid interactions are absent for polypeptides in the random coil conformation.
www.wordiq.com /definition/Random_coil   (332 words)

 Poly Glutamine Repeats   (Site not responding. Last check: )
AKQ17 responds to the addition of TFE at the expense of all sheet and some random coil (64% of helix, 36% coil at 40% TFE), with most of the poly-Q remaining in a coil conformation.
Following this trend of increasing coil content with shorter alkyl chains, one would expect polyglutamine itself to be a coil rather than a helix.
We have shown that the polyglutamine stretches in the water soluble peptides AKQ9 and AKQ17 adopt a random coil conformation.
www.ruppweb.org /cd/polyq.htm   (1477 words)

 k2d.read.me   (Site not responding. Last check: )
The 1st has the wavelength values, the 2nd is the CD spectra of the sample, and the 3rd has the mean CD spectra value of the winning neuron for the 100 sets of training weights contained in weights.dat.
Additionally, it gives the square of the euclidean distance between the real and the winning neuron CD spectra, and, acordingly to this distance, the estimation of the mean error in the prediction of the three secondary structure values.
This means that the sum of the errors in the prediction of the alpha, beta and random percentage values divided by three is expected to be less then 0.08.
www.embl-heidelberg.de /~andrade/k2dreadme.html   (355 words)

 A Systematic Study of the Vibrational Free Energies of Polypeptides in Folded and Random States -- Ma et al. 79 (5): ...
One random conformer is chosen as the unfolded structure for each protein.
One random conformer is chosen as the unfolded structure for each of the proteins, 2abl (red) and 1b07 (green).
The broad distribution of the random conformations are expected to represent the folding energy landscape.
www.biophysj.org /cgi/content/full/79/5/2739   (4976 words)

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