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Unlike other structure determination methods, with x-ray crystallography, there is no fundamental limit on the size of the molecule or complex to be studied. However, in order for the method to work, a pure, crystalline sample of the protein must be obtained. For many proteins, including many membrane-bound receptors, this is not possible. In addition,a single x-ray diffraction experiment provides only static information - that is, it provides only information about the native structure of the protein under the particular experimental conditions used. As we will see later, proteins are often flexible, dynamic objects when in their natural state in solution, so a single structure, while useful, may not tell the full story. More information on X-ray Crystallography is available at Crystallography 101 and in the Wikipedia .

Nmr

Nuclear Magnetic Resonance (NMR) spectroscopy has recently come into its own as a protein structure determination method. In an NMR experiment, a very strong magnetic field is transiently applied to a sample of the protein being studied, forcing any magnetic atomic nuclei into alignment. The signal given off by a nucleus as it returns to an unaligned state is characteristic of its chemical environment. Information about the atoms within two chemical bonds of the resonating nucleus can be deduced, and, more importantly, information about which atoms are spatially near each other can also be found. The latter information leads to a large system of distance constraints between the atoms of the protein, which can then be solved to find a three-dimensional structure. Resolution of NMR structures is variable and depends strongly on the flexibility of the protein. Because NMR is performed on proteins in solution, they are free to undergo spatial rearrangements, so for flexible parts of the protein, there may be many more than one detectable structures. In fact, NMR structures are generally reported as ensembles of 20-50 distinct structures. This makes NMR the only structure determination technique suited to elucidating the behavior of intrinsically unstructured proteins , that is, proteins that lack a well-defined tertiary structure. The reported ensemble may also provide insight into the dynamics of the protein, that is, the ways in which it tends to move.

NMR structure determination is generally limited to proteins smaller than 25-30 kilodaltons (kDa), because the signals from different atoms start to overlap and become difficult to resolve in that range. Additionally, the proteins must be soluble in concentrations of 0.2-0.5 mM without aggregation or precipitation.For more information on how NMR is used to find molecular structures, please see NMR Basics and The World of NMR: Magnets, Radio Waves, and Detective Work at the National Institutes of Health's The Structures of Life website.

Electron diffraction

Electron diffraction works under the same principle as x-ray crystallography, but instead of x-rays, electrons are used to probe the structure. Because of difficulties in obtaining and interpreting electron diffraction data, it is rarely used for protein structure determination. Nevertheless, ED structures do exist in the PDB. For more on ED, see this Wikipedia article .

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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Source:  OpenStax, Geometric methods in structural computational biology. OpenStax CNX. Jun 11, 2007 Download for free at http://cnx.org/content/col10344/1.6
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