The role of the α-helix dipole in protein function and structure

The structures of deuterated ices VI, VII, and VIII have been studied under their conditions of stability by neutron powder diffraction. The mode of ordering of (tetragonal) ice VIII is clearly established, and no evidence is found of partial ordering as the temperature is raised. Ice VII is accurately cubic with D2O molecules disordered around their center of mass; there is no evidence of partial ordering at any temperature. The water molecule geometry is normal in both phases, and the hydrogen‐bonded first neighbor in ice VIII is confirmed to be more distant than the first nonbonded neighbor. The transition temperature between the two phases occurs at 263±2 K, some 11 K lower than expected. Hydrogen bond lengths in both phases are equal at the transition. Although the ice VI data are not as good, we can see no evidence of the antiferroelectric ordering proposed by Kamb from work on recovered samples. Our results are consistent with thermodynamic measurements indicating disorder in ice VI at 193 K. We co...

Structure and hydrogen ordering in ices VI, VII, and VIII by neutron powder diffraction

Lattice dynamics calculations have been carried out for ice Ih using the SPC rigid‐molecule effective pair potential whose parameters were fitted to the properties of water. We employ a periodically replicated nonpolar sample of 128 molecules whose constituent molecules are arranged according to the ice rules. Long range dipole–dipole interactions are handled using the Ewald method. The calculated density of states in the translational and librational regions accords well with available experimental data. However, the frequency of the longitudinal optic mode is a little low as is the position of whole librational band. Although polarization (induction) effects are not explicitly included in the calculation of the vibrational frequencies and their associated eigenvectors, they are invoked to evaluate the quantities which determine the infrared absorption, namely, derivatives of the crystal dipole moment with respect to the normal coordinates. The overall features of the infrared spectrum for translational ...

Lattice vibrations and infrared absorption of ice Ih

Dimer energy surfaces for three models of the water-water interaction are examined and compared with high level ab initio SCF calculations for two important sections. All three models studied (ST2, MCY, and PE(Q) show significant differences which would be expected to be important in full liquid state simulation; the inclusion of an additional dipole-octupole term in PE appears sufficient to reproduce the energy-angle variations shown in the SCF calculations. ST2 distinguishes too strongly between the lone pairs on the acceptor water molecule, while MCY shows little sign at all of lone pair separation. All three models disagree with the rotational barrier heights given by the SCF calculations; these differences we would expect to have structural consequences in a room temperature liquid ensemble. Although there are insufficient experimental and numerical data available to fully test the three-body (and higher) interactions of the PE model, good agreement is obtained with experimental enhanced dipole momen...

Two, three, and four body interactions in model water interactions

Water plays more than a passive role in biomolecular processes that occur in aqueous media. Much of its involvement is often assigned to the so-called “hydrophobic interaction”, a process which, although well-characterised thermodynamically1, is poorly understood at the molecular level. In addition, there are other potentially large contributions to free energy changes accompanying such processes as protein-substrate binding or protein folding. These relate to hydrogen-bonding and entropic changes involving the solvent region2 and are similarly poorly understood.

The Structure and Dynamics of Water in Globular Proteins

Using a previously developed non-pair-additive model of the water–water hydrogen bond, the relative stabilites of hydrogen ordered and disordered ice Ih, ices VII and VIII are examined. The results are consistent with both the observed hydrogen-ordering in the VII → VIII transition, and the lack of any similar ordering in hexagonal ice I. The symmetry relation between the two sub-lattices of VII and VIII, together with the non-linearity of the energy of the dipole–dipole interaction, suggest such ordering transitions may be favoured only when very special symmetry arrangements result in the cancellation of certain electropole energy terms.

Cooperative and quadrupole effects in order-disorder transitions in crystalline ices

Structure and hydrogen ordering in ices-vi, ices-vii, and ices-viii by neutron powder diffraction

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Dv Bliss

Author Tools

Chat about Author

Papers

Cooperative and quadrupole effects in order-disorder transitions in crystalline ices

Structure and hydrogen ordering in ices-vi, ices-vii, and ices-viii by neutron powder diffraction