November-December 2011
circulation this issue: 6,896
|
November-December 2011circulation this issue: 6,896 |
 |
||
 |
 |
|
New from MiTeGenCustomer ContributionsProduct HighlightsOther News |
WelcomeWelcome to the November-December Mitegen Newsletter.
This month, Briony Yorke of Leeds discusses progress in simultaneously gathering X-ray diffraction and spectroscopy data, on microcrystals using Mitegen MicroCrytal Mounts.
Our monthly Tech Tip this month focuses on reducing ice formation and buildup during data collection.
Customer feedback on our products and newsletter is always welcome. * new: follow us on facebook: |
|
 |
||
 |
 |
|
|
New from MiTeGenAngled Tip Option for improved Data CollectionMany crystal forms (e.g., thin plates) adhere to a loop / mount so that one crystal axis is perpendicular to the mount. This can cause diffraction spot overlap during data collection, especially for crystals with highly anisotropic unit cells. Angled tips allow you to:
All styles of MicroMounts™, MicroLoops™, and MicroMeshes™ can be ordered with an Angled Tip Option. 
| |
 |
||
|
|
|||||
|
Customer ContributionSimultaneous Diffraction and Spectroscopic Data From Microcrystals
By: Briony Yorke
|
|||||
|
The MicroCrystal Mounts™ were tested using the online UV-Vis microspectrophotometer at Diamond Light Source (beamline I02). UV-Vis absorption spectra were recorded from 200 nm to 750 nm. 
Figure 1: Spectrum of myoglobin thin-film in nylon loop. Figure 1 shows the absorbance of the empty nylon loop. Thin films of ~5 mM myoglobin in 50% MPD (20 μm thick) were applied to the mounts and cooled to 100 K in the cryostream, all data were collected at 100 K. The spectra of the empty polyimide loops were used as a reference. 
Figure 2. Spectra of myoglobin thin films on MicroCrystal Mounts. The spectra in figure 2 show that the MicroCrystal Mounts™ designs M4 Model #2 and #3 give the best results.
Figure 3. Mitegen MicroCrystal Mounts™ Models #2 and #3 The spectra are almost identical to that of a thin film in a nylon loop, however there is a small increase in noise in the UV region. Interference patterns were observed on the spectra recorded using all of the other MicroCrystal Mounts™ designs tested and so these are unsuitable for collecting UV-Vis spectroscopic data, especially where important absorption features are observed in the range 450 – 750 nm. We also noted that, in all cases, the edges of the mount interfere with the spectra at lower wavelengths due to the increase in polyimide thickness around the edge of the mount. Our observations show that the MicroCrystal Mounts™ (M4, Model #2 and #3) are suitable for use in collecting single crystal UV-Vis spectra, provided that a) a reference spectra is taken from the empty mesh and b) that the thicker edge of the loop is avoided.
About Dr. Arwen Pearson's Group
About Briony Yorke |
||||||
|
||||||
|
|
|
|
MicroCrystal Mounts™Specifically designed for:
These ultra-transparent mounts meet the challenges of visualizing, aligning, and collecting diffraction data from micron size crystals. Using dual-thickness technology, crystals are supported on a 3 micron thick film in a 10 micron thick frame. An aerodynamic design combined with a shorter tip length minimizes sample motion. MicroCrystal Mounts™ provide an a unsurpassed combination of X-ray transparency and rigidity. 
| |
|
||
 |
||
|
Customer Quote: "We have been extremely impressed by Mitegen's dedication to innovative design and constant attention to the needs of users. The mesh and gripper designs have allowed us to obtain useful data from thin crystals that would otherwise be damaged by mounting on traditional fibre-based loops. Mitegen's new designs continue to push the envelope for assisting with the consistent and convenient mounting of microcrystals. We look forward to continue working with Mitegen as they continue to refine their designs and respond to the needs of users"
Dr. Ken Ng |
||
 |
||
|
|
|
|
Jena Bioscience product highlightJBScreen Family - JBScreen PentaerythritolJBScreen Pentaerythritol has been designed for efficient crystallization screening of biological macromolecules based on pentaerythritol polymers as precipitants. The screen was developed by Ulrike Demmer from the Max-Planck-Institute for Biophysics in Frankfurt. The choice of a suitable precipitant is of crucial importance for the crystallization of proteins. JBScreen Pentaerythritol utilizes two novel precipitating agents, i.e. pentaerythritol propoxylate and pentaerythritol ethoxylate. Both are branched polymers containing a pentaerythritol backbone. Thus they differ from more traditional precipitants like MPD and PEG’s in size and nature. In addition, pentaerythritol polymers function as cryoprotectants. Protein crystals grown in high concentrations of these precipitants can be frozen directly from the crystallization drop. The successful application of pentaerythritol polymers to yield protein crystals was first described by Gulick et al. [1]. Now this class of precipitants has been used for membrane crystallization, too. The X-ray structure of cbb3 Cytochrome Oxidase was recently published in Science [2]. Crystals of this proton pumping membrane protein were successfully grown using pentaerythritol ethoxylate as precipitation agent. JBScreen Pentaerythritol comprises of 96 unique conditions, based on 4 different pentaerythritol polymers as precipitating agent:
The 4 polymers are arranged to a grid screen, thus allowing screening i) of three different precipitant concentrations, ii) four different pH values and iii) with and without the addition of salts, i.e. magnesium chloride, ammonium sulfate, potassium chloride. The advantage of JBScreen Pentaerythritol not only lies in the novel 96 conditions but also in the systematic arrangement of the unique reagents, which enables the user to compare individual conditions directly. Even if initial screening may not always yield crystals, valuable information about the protein under investigation can be obtained from the scoring sheet.
References |
|
|
||
 |
||||||
|
Customer Quote:
"Mitegen's RT system is very handy and useful for room temperature measurements.
It makes life easy in handling crystals at room temperature. We have been
extensively using it for our room temperature studies. It was also very helpful
in dehydration studies. In fact we also use Mitegen meshes for handling our
micro crystals, which is excellent.
Rajendran Chitra |
||||||
 |
||||||
 |
||||||||||
|
|
|
||||||
|
| |||||
|
The Capillary Boy is manufacturered by Huber Diffraktiontechnik GmbH & Co., and is distributed by Mitegen in the Americas under agreement with AJK Analytical Services. For sales outside the Americas, contact at AJK Analytical Services info@ajk-analytical.com |
||||||
|
||||||
 |
||||||
|
Customer Quote: "We've found that using MiTeGen loops lets us pick and mount crystals much more quickly than using glass fibers, which means we can more-rapidly screen crystal samples and minimize the time that sensitive samples have to spend in contact with the air, where they can decompose or dissolve."
Nathan Schley |
||||||
 |
||||||
|
|||||||||
|
| ||||||||
|
|||||||||
 |
||||
Monthly Tech TipMinimizing Ice Accumulation on Your Sample During Data CollectionFrosting - the formation of ice crystals near and on the sample - can be a nuisance during data collection. Frost generates ice rings in diffraction patterns. It can also perturb cryostream flows and increase turbulence, leading to more frosting and to sample motion. Frosting is generally due to a combination of unsteady / turbulent gas flow near the sample and high ambient humidity. If gas flows are laminar and steady in the vicinity of the sample, you should get very little icing. But any turbulence creates eddies that can entrain moist air from the surroundings and condense it on your sample. How can you reduce frosting/icing? Adjust the cold gas stream and the surrounding shield flow to minimize turbulence. With modern gas stream equipment, following the manufacturer’s instructions generally gives the best results. Older systems can be a bit tricky and can require some trial and error experimentation. Make sure that the gas stream hose feels warm to the touch. Partial loss of vacuum (and thus thermal insulation) in the gas stream’s flexible hose, or ice accumulation inside the flow tubes, can cause fluctuating gas flows and gas temperatures. They can also increase gas flows required to achieve a given stream temperature. Both will increase turbulence around the sample. Make sure that the gas stream is properly centered on the sample, and that the distance from the gas stream tip to the sample is as recommended by the cold stream manufacturer. Generally, closer is better, but too close and the gas stream hits the goniometer base too forcefully and generates too much turbulence. All of the ice that deposits on your sample is due to water vapor entrained from the surrounding air by turbulent vortices. In the summer when humidities are high, this can be a particular problem. Possible solutions:
Contact Us with comments or suggestions |
||||
 |
||||
|
||
Select Recent Citations
Every month, the use on Mitegen products is cited in dozens of papers. Here is a small selection of recent citations: Wei Liu, Vadim Cherezo (2011) Crystallization of Membrane Proteins in Lipidic Mesophase , Journal of Visualized Experiments Robert G. Denning , Jeffrey Ronald Harmer , Jennifer Clare Green , and Mark Irwin (2011) Covalency in the 4f Shell of tris-cyclopentadienyl Ytterbium (YbCp3) – a Spectroscopic Evaluation. , J. Am. Chem. Soc. Nora C. Breit, Travis Ancelet, J. Wilson Quail, Gabriele Schatte, and Jens Müller (2011) Synthesis of Intramolecularly Coordinated Aluminum and Gallium Compounds for the Preparation of [1]Ferrocenophanes , Organometallics, 2011, 30 (22), pp 6150–6158 Ankan K. Dhal, Sourav Chatterjee, Daniel J. Sandman, C.-H. Chen & Bruce M. Foxman (2011) Co-crystals of Isonicotinamide and p-Cyanobenzoic Acid , Journal of Macromolecular Science, Part A, Volume 48, Issue 12, 2011 Venugopal Thottempudi and Jean’ne M. Shreeve (2011) Synthesis and Promising Properties of a New Family of High-Density Energetic Salts of 5-Nitro-3-trinitromethyl-1H-1,2,4-triazole and 5,5′-Bis(trinitromethyl)-3,3′-azo-1H-1,2,4-triazole , J. Am. Chem. Soc. Rodney L. Willer,*, Robson F. Storey, Mark Frisch, Jeffery R. Deschamps (2011) Crystal structures of the “two” 4-aminofurazan-3-carboxylic acids , Journal of Heterocyclic Chemistry Miriam M. Gillett-Kunnath, Joseph I. Paik, Sara M. Jensen, Jacob D. Taylor, and Slavi C. Sevov (2011) Metal-Centered Deltahedral Zintl Ions: Synthesis of [Ni@Sn9]4- by Direct Extraction from Intermetallic Precursors and of the Vertex-Fused Dimer [{Ni@Sn8(μ-Ge)1/2}2]4- , Inorg. Chem., 2011, 50 (22), pp 11695–11701
|
||
|
||
|
||||
Proudly DistributesIn addition to Mitegen's proprietary line of innovative products, Mitegen is also a proud reseller of industry leading products from these fine companies: |
||||
|
|
|||
|
||||
|
||||||
Send Us Your
|
More at:
|
Let our innovators
|
||||
|
Copyright © 2011 MiTeGen, LLC. All rights reserved. |
||||||
|
||||||
