Kayla Green’s favorite structure is:

photosynthetic reaction center structure in membrane

Why?

I had the great pleasure of getting to know Dr. Johann Deisenhofer during my post-doc at UTSW.  He was awarded the 1988 Nobel prize determining the structure of an intermembrane protein and I enjoyed hearing about his early career.  Although I am a small molecule crystallographer, this structure reminds me of the wonderful man and scientist that I unexpectedly had the pleasure of getting to know at UTSW.  —Kayla Green

Byron Delabarre’s favorite structure is:

Carbonic Anhydrase

CA-rasmol

Source: http://www.rcsb.org/pdb/education_discussion/molecule_of_the_month/images/CA-rasmol.gif

Why?

Maybe not so sexy compared to DNA, ribosome & GPCR structures we see touted as the major achievements of structural biology, but carbonic anhydrase was the first protein structure I ever studied in detail.  I had just started a
graduate course in bioinorganic chemistry where I had decided to cover proteins using Zinc at the active site.  I had never taken a biology or biochemistry course prior to this, thinking myself strictly a synthetic organic chemist. I was hooked immediately by the language, the images and of course the amazing science.  That particular protein structure started me on a path of structural biology understanding that has served me for nearly 20 years now. Even cooler that it came from the lab of T. Alwyn Jones, whose program ‘O’ was a source of frustration (seriously, who names a command after a hobbit? ‘sam_atom_in’!), but mostly delight as a companion when I started solving my own structures.—Byron Delabarre

Alexandre Giguere’s favorite structure is:

1QD7

Source: Nature

Why?

Bacterial resistance to antibiotic compounds is a growing problem the world will have to face in the next century. The knowledge of how some antibiotics affect the ribosome is and will be of primordial importance in the fight against resistant bacteria. Several other structures of antibiotics bounded ribosome have been produced by Ramakrishnan et al. during that time.
Nature, VOL 400, 26., p. 833—Alexandre Giguere

Jes Sherman’s favorite structure is:

Pentacene

ink

Source: Mine, and I have a higher-resolution image of the design if that’s preferred.

Why?

Pentacene is one of the lab rats of organic electronics. It has been widely studied in the solid state, grown into thin films, and derivatized for improved solubility or different packing or more interesting electronic properties. The structure that is tattooed on my back is not surprising, crystallographically—there are plenty of organic compounds that crystallize in triclinic space groups and exhibit herringbone packing motifs. It is not even the only crystal structure reported for this molecule.  Like many compounds, pentacene exhibits several polymorphs; this one is observed in single crystals.

This structure is not my favorite because of the molecule itself, but because of all the research it has enabled—including my own PhD investigations. Crystal structures provide great insight into the physical properties of organic semiconductors. We can use the information in a .cif file to calculate electronic structure or predict crystal habit. Beyond single crystal structure determination, diffraction data are useful in exploring interesting physical properties such as negative thermal expansion (which pentacene exhibits along its a axis) and determining how well ordered thin films are. In the right hands, a crystal structure is a very useful tool.—Jes Sherman


Terry Bigioni’s favorite structure is:

Na4Ag44(pMBA)30

Na4Ag44(pMBA)30 favorite crystal structure copy

Source: Nature Materials

Why?

Crystals of the molecular silver nanoparticle Na4Ag44(pMBA)30 are the first molecular framework materials made from nanoparticles, which is a new class of materials. Approximately 50% of the volume of the crystal is void space. When compressed, the crystal becomes a molecular machine with concerted mechanical motion of its building blocks. This surprising and dramatic collective motion leads to a negative Poisson ratio. Auxetic materials such as this are very rare and can have very different properties than conventional materials. A mechanical study of this material appears in the August 2014 issue of Nature Materials.

The crystal structure of individual Na4Ag44(pMBA)30 molecular nanoparticles is also very important as it gives the first detailed view of the Ag-S interface, which is extremely important for understanding the nature and chemistry of thiolated silver nanoparticles. It also happens that this nanoparticle is the first to be produced on a massive scale in pure form, with a 140 gram batch demonstrated. Further, this nanoparticle is anomalously stable, more stable than even gold nanoparticles of the same class. This was reported in the September 19, 2013 issue of Nature.

The Na4Ag44(pMBA)30 crystal structure is my favorite for what it is and for what it can DO.—Terry Bigioni


Claire Tessier’s favorite structure is:

[Cr(CO)5(PPh2(CH2)4OAl(CH2SiMe3)2]2

OM-83-1128-[Cr(CO)5(PPh2(CH2)4OAl(CH2SiMe3)2]2

Source: I generated the picture from the CIF file in the Cambridge Crystallographic Database that is associted with the reference: Organometallics 1983,2, 1128-1138.

Why?

This crystal structure is important to me for several reasons:
1) It was pivotal for understanding the THF cleavage that was occurring in my PhD research project. The structure shows an opened THF molecule in between the Al and P atoms.
2) It was the first published collaborative work between my husband (Wiley Youngs) and me. He was the crystallographer and at the time was also a grad student.  We have been collaborating ever since (~86 publications).
3) It was the first published collaborative work between my husband’s (Churchill) and my (Beachley) research advisors.  They went on to publish a total of ~33 papers together.
The crystal structure was published in C. Tessier-Youngs, Wiley J. Youngs, 0. T. Beachley, Jr., and Melvyn Rowen Churchill Organometallics 1983,2, 1128-1138. —Claire Tessier


Divneet Kaur’s favorite structure is:

methyl α-(5,6-dimethoxycarbonyl-2,3-dimethoxyazepin-7-ylidene)-α-[5-methoxycarbonyl-2,3-dimethoxypyrid-6-yl)acetate

Viswamayene

Source: Eswaran et al, J. Het. Chem., 1996, 33(4), 1333

Why?

The compound is also called as ‘Viswamayene’. The crystal is one of its kind of a small organic molecule with M.Wt= 534. It is a highly unusual compound in its formation and structure and is formed from a ‘long lived’ singlet nitrene species generated from a tetra substituted aryl azide. The compound is formed via a concomitant ring expansion and ring extrusion reaction, thereby leading to a formation of a pyridyl carbene species from a nitrene. The unusual and un-precedented reaction finds no alternative in literature and forms the basis of another set of rather similar unusual compounds reported from my laboratory which is also a part of my Ph.D thesis work. I feel, that X-ray played a crucial role in determining the exact structure of the compound as NMR techniques were not too sophisticated at that time. The compound gives a rare evidence for the formation of a pyridyl group from a benzene molecule by a series of rearrangements. I, thus feel that this highly unusual molecule has no precedence in literature and hence should be highlighted and recognised for its rare mechanism of formation. —Divneet Kaur


Isaac Yonemoto’s favorite structure is:

Insulin Hexamer (1ai0)

Insulin Hexamer (1ai0)

Source: Selfmade, using PyMol

Why?

I’ve loved this structure for over 8 years (I made the similar one, derived from an NMR structure, featured on insulin wikipedia page since ’06). Despite extreme effort to obtain beautiful crystals – some were even grown on the space shuttle – EM diffraction shows no evidence that insulin is crystalline in higher therians. The b-chain strands are in an antiparallel beta sheet, tantalizingly wrong for understanding parallel beta-sheet amyloid assembly of insulin, which occurs via these residues. A hyperconserved lysine (except, oddly, in rodent insulin 1) is very likely salt bridging in ‘real insulin’ but is seen in an artefactual cystallographic interactions in this structure. A calcium ion, believed to reside in biological formulations, is missing, because the inclusion of calcium ions leads to uncontrollable precipitation. In short, these structures, discovered relatively early and continously refined, are symbolic of the human tendency to seek beauty over reality, and for that reason I love it, C3- and pseudo-C2 symmetries and all. But beauty may not necessarily be useless: These structures have been instrumental in guiding the design of the bestiary of reformulated insulins over the decades. —Isaac Yonemoto


Kate Stafford’s favorite structure is:

Ribonuclease H1 (2QK9)

Ribonuclease H1 (2QK9)

Source: Kate Stafford

Why?

It’s my PhD protein! RNase H is an enzyme that cleaves DNA-RNA hybrids that is found in all domains of life. RNases H from mesophilic and thermophilic bacteria were among the first homologous structures solved from organisms adapted to different temperatures and are structurally very similar despite large differences in enzymatic activity. My work used molecular dynamics simulations to interpret NMR measurements of these proteins’ internal dynamics to better understand the relationship between motion, function, and thermal adaptation.

The PDB code cited above (2QK9) is that of the human RNase H homolog, which was solved in the presence of a hybrid substrate.

RNase H is essential in higher eukaryotes, so everyone reading this has a functional one. It is also essential for the proliferation of retroviruses, making selective inhibitors of the retroviral RNase H domain a potential drug target for novel HIV treatments.

The attached photo is the human RNase H 3D printed with Shapeways. —Kate Stafford


Ashutosh Jogalekar’s favorite structure is:

Alpha hemolysin

Alpha hemolysin

Source: Wikipedia (PDB code 7ahl)

Why?

Alpha hemolysin is one of the very few protein structures that’s not only breathtakingly pretty and intricate but which is also the epicenter of a true technological breakthrough.

The entire structure resembles a flower and traverses a membrane. Beta sheets run along each other to form a 14-strand beta barrel ‘stem’ while other beta sheets line up next to each other at the rim to form the ‘petals’. Both these substructures enclose a remarkable, 100 A long solvent-filled channel. And most impressively, all these subunits self-assemble.

The practical reason why alpha hemolysin is so fascinating is because it is the linchpin of next generation DNA sequencing technology. By utilizing the solvent-filled channel as a nanopore, researchers are threading DNA strands through it and sequencing individual nucleotide bases by looking at minute changes in electrical current across the pore. The technology has already been commercialized and promises to reduce both the cost and time of sequencing.

Alpha hemolysin is thus one of the most perfect examples of combining elegant form with breakthrough technological function. It’s as good an example as I know of nature’s unsurpassed ability to create both beauty and utility in one fell swoop. —Ashutosh Jogalekar


Pennarun’s favorite structure is:

Snowflakes hexagonal struture

Snowflakes hexagonal struture

Source: http://en.wikipedia.org/wiki/X-ray_crystallography#mediaviewer/File:Snowflake8.png

Why?

Water is one of the simplest molecule on earth and essential to life. Well known molecule, it is in the same time a molecule that still not completely known when grouped with other water molecule. Snowflakes show broad number of structures, from which mechanical behavior will depend. Macroscopic mechanical behavior of snow, especially in montains, depends then only of the weak very small hydrogen bonds. In the same time not so weak as USA think to use it with wood fibers to build armor for warships as strong as metallic ones during the WWII. —Pennarun


Marc Armbrster’s favorite structure is:

CuAl2

CuAl2

Source: My PhD thesis :-)

Why?

The intermetallic compound CuAl2 helped to reveal that the chemical bonding depends on the elements in a series of isostructural compounds and not on the crystal struture. Besides, it is one of the best examples that simple metals like copper and aluminum can form beautiful crystal structures upon compound formation! —Marc Armbrster


Xin Su’s favorite structure is:

Insulin/4-hydroxybenzamide on space mission STS-60

Insulin/4-hydroxybenzamide on space mission STS-60

Source: PDB

Why?

Despite many insulin crystal structures you may find in the Protein Data Bank, this one is extraterrestrially exotic. In addition to its exquisite beauty, grown under microgravity aboard the Space Shuttle Discovery, the high-quality crystal enabled scientists to reveal the fine details about drug-insulin interactions, which would have been impossible with earth-grown ones. —Xin Su


Kelly Tyrrell’s favorite structure is:

MreB

Evolution of the cytoskeleton JCB

Source: The Journal of Cell Biology

Why?

Prior to the advent of x-ray crystallography, one of the defining characteristics of prokaryotes was “lacks a cytoskeleton.” However, when the crystal structure of bacterial MreB was found, scientists discovered that MreB and eukaryotic actin “look” nearly identical. It turned that notion completely upside down, rewriting textbooks, and scientists have been studying these homologs – and the evolutionary origins of these proteins – ever since. —Kelly Tyrrell


Miranda Paley’s favorite structure is:

1FKA

1fka_asr_r_250

Source: PDB

Why?

Because: it’s the freaking ribosome! While later structures provided better resolution, this structure is the hallmark of visionary Ada Yonath’s career. She was ridiculed for so many years about trying to crystallize the ribosome, and she finally got it! The additional work on the paper modeling in tetracycline to show its mode of action and to further validate the solution to the structure is also well done. —Miranda Paley


George Oh’s favorite structure is:

i-YbCd5.7

Why?

There is such high symmetry – concentric shapes within shapes, starting with platonic solids and going into bigger polyhedra to fit the number of atoms. The shapes are also interwoven with each other, and the viewer can find a multitude of shapes of all sorts of symmetry. It’s like playing with shape tiles in elementary school, but in 3d! —George Oh


Stephanie Taylor’s favorite structure is:

DNA

Stephanie Taylor

Source: Stephanie Taylor

Why

DNA says so much in a single picture. First, getting students to have an idea of what x-ray crystallography IS can be difficult. They have been seeing this odd black and white picture in chapters on DNA in their textbooks since high school, so it obviously has a biology connection.

Second, it connects the importance of the contribution of women in science. Rosalind Franklin not only discerned that the phosphate backbone was on the OUTSIDE of the structure, she also was among the first to crystallize the B form of DNA, which created clearer x-ray diffraction patterns and is more biologically relevant.

Finally, though it is well known, DNA is far from a cliche molecule. Its versatility and stability fascinate biologists, chemists, engineers, and physicists. Every field has a niche for it.

I am certain you will get this answer often, and for the best of reasons — while we have beautiful structures of many things of importance, you will find it difficult to find a scientist (amateur to professional) who is unfamiliar with the beauty of their own legacy and lineage: DNA. —Stephanie Taylor


Vito Capriati’s favorite structure is:

α-Lithiated oxirane

Lithiated_epoxide

Source: Chemical Science 2014, 5, 528-538

Why

This is the first crystallographic evidence for the structure of a highly reactive lithiated aryloxirane (t½ = 1.6 s at 157 K in THF). All operations were carried out under a nitrogen atmosphere at the temperature of 100 K. α-Lithiated oxiranes have long considered “fleeting” intermediates in the reaction of epoxides with strong bases, but have nowadays proven to be key synthons for asymmetric synthesis. They are small-ring heterocycles carrying a peculiar polarized Li-C bond which gives them the character of “carbenoids”, thereby exhibiting an amphiphilic behaviour, that is a nucleophilic as well as an electrophilic reactivity. In spite of their widespread use in synthetic strategies, however, information about the reactivity and structural features of these species were lacking before publishing these data. Indeed, It was as well long postulated that was an alkoxy carbene, in equilibrium with the lithiated epoxide, responsible of the carbene-like reactivity observed under certain experimental conditions. The knowledge of the solution and the solid structure of these intermediates may set the scene for future development in the field of α-lithiated epoxides and for controlling stereochemistry in C–C bond forming reactions onto an oxirane moiety. —Vito Capriati


Ombretta Masala’s favorite structure is:

Franklin’s famous “photograph 51” that finally revealed the helical structure of DNA

x-ray

Source: www.nobelprize.org

Why?

It was Franklin’s famous X-ray diffraction photo that finally revealed the helical structure of DNA to Watson and Crick in 1953.

It is my favourite because it solved the puzzle of the elusive structure of the DNA and I like the story behind. Franklin was robbed of recognition because Photo 51 enabled Watson, Crick, and Wilkins to deduce the correct structure for DNA, which they published in a series of articles in the journal Nature in April 1953 without Franklin. Franklin’s image of the DNA molecule was key to deciphering its structure, but only Watson, Crick, and Wilkins received the 1962 Nobel Prize in physiology or medicine for their work (Franklin died four years earlier and Nobel prizes aren’t awarded posthumously).

It is thought as one of the most well-known—and shameful—instances of a researcher being robbed of credit and in particular of a woman scientist who was snubbed due to sexism. —Ombretta Masala