To enable iron diffusion, Escherichia coli bacteria have siderophores on their outer membrane called FecA. FecA is composed of three distinct domains. The binding of iron citrate will induce an allosteric change in the membrane protein, which will propagate and allow iron entry. This structure, PDB 1KMP, was realized by crystallography. I show this FecA protein integrated into a membrane (yellow lipids). Iron, red spheres, is in complex with citrate, in blue. One of the iron citrates is fixed inside the FecA protein. A light show is used to distinguish the outside from the inside of the bacteria.

Image shown exhibit the newly discovered asymmetrical beauty of nature and the living fossil enzyme DPOR. DPOR stands for dark operative protochlorophyllide oxidoreductase and is an ancient enzyme responsible for photosynthesis in dark. DPOR complex exist as two component protein, the electron donor component BchL (exist as dimer) and the electron acceptor component BchN-BchB (exist as hetero-tetramer). Based on the X-ray crystallography, this enzyme complex was believed to exist as a symmetrical complex with the ratio of BchL:BchN-BchB as 2:1. Using the Cryo-EM technique we discovered this complex indeed exist as an asymmetrical complex with the ratio of BchL:BchN-BchB as 1:1 in the turnover condition.

Reference: https://www.biorxiv.org/content/10.1101/2024.04.26.590571v1

The artwork shows the cryo-EM structure of V-ATPase at 3.6 Å (state 1) with synaptophysin in native synaptic vesicles (SV) from rat brain (PDB: 9BRB). This structure was recently published in Science (Coupland et al., Science, 2024). SVs were identified in cryo-EM micrographs using a custom algorithm, VesiclePicker, in combination with single-particle to calculate 3D maps of the enzyme. Vesicles are depicted as colorful spheres in the background of the artwork. The prominent part of the artwork shows the V-ATPase structure protruding from the native membrane of SVs. Synaptophysin binds the V-ATPase complex stoichiometrically, and cholesterols decorate the enzyme’s rotor.

Aquaporins are channel proteins which facilitate the movement of water across cell membranes. From the smallest microorganism to the largest mammals, every life form depends on water for proper functioning at the molecular level, thus making Aquaporin the seasoned conductor of the beautiful interconnected tapestry named life. 

Reference: https://doi.org/10.1371/JOURNAL.PBIO.1000130

Trypanosomes are curly, 15 µm-long and 2 µm-thick unicellular eukaryotic organisms, used as models for human ciliopathies. Their flagellum, attached to their cell body via staples, is important for locomotion and cell division. However, how it is attached while still being able to elongate/grow is not fully understood yet. For the first time, using cryo-scanning transmission electron tomography a new method capable of imaging biological samples up to ≈1.5 µm, entire trypanosomes were studied which unveiled the irregular staple organisation, previously thought to be regular. This study led to a new flagellum elongation model.

A molecule is depicted splashing into a pool of water. To scale, the water is only tens of nanometers deep. This is thin enough to be transparent to electrons, enabling electron microscopes to see molecules dissolved in water. This technique was used to determine the structure of the depicted molecule, a protein called the parathyroid hormone receptor (PDB: 8FLT).

Human 12-lipoxygenase (12-LOX) is an iron-containing enzyme involved in platelet activation. Here I show the hexameric form of 12-LOX bound to the inhibitor ML355 (PDB ID = 8GHD, EMDB=40041). The protein is shown as rusted iron-textured ribbons and the ligands as glowing molten spheres.

I am a scientist using cryo-electron microscopy to determine structures of GPCRs to try and find more about how they work!. This is a photo taken from a pretend Monash campus news article published in 2014, when cryo-EM had a 'resolution revolution', and some excited students went a bit too far.... I made this font out of 10 different GPCR structures publicly available in the PDB: G = GLP-1R (6X18) P = PAC1R (8E3X) C = CCK-1R (7MBX) R = Rhodopsin (6OFJ) S = 5HT1AR (7E2X) R = RXFP1 (7TMW) O = muOR (8K9L) C = CTR (5UZ7) K = Kisspeptin (8ZJE)  = VPAC1R (6VN7).

The image shows a variety of the protein actinoporin on a liposome. This is a pore-formin toxin present in the poison of the Sun Anemone. (The protein structure has been provided by the researcher Jaime Martin Benito (CNB.CSIC)).

By playing with molecular building blocks for billions of years, nature’s playfulness and creativity has culminated in the the most beautifully designed molecular machines: enzymes. This artwork aims to honour this act of playful creation and make the heart of every scientist’s inner child beating faster. Who wouldn’t love to play with one’s favourite enzymes? The rendering is based on one of our published cryo-EM structures of the AAA-ATPase Drg1, assembled at its native substrate, the precursor of the large ribosomal subunit, also called pre-60S particle (Prattes et al., 2022, NSMB, PDB 7Z34).

Membrane-bound transporters at the cell surface engage in absorption and excretion of nutrients, drugs, and toxins, acting as molecular gates for cargo into our bodies. The particular transporter depicted here (SLC22A1) selectively moves positively charged molecules in a rocker-switch mechanism, rocking between an “A” shape (left half) to release cargo (white) and a “V” shape (right half) to capture cargo. With recent structural information from cryo-EM, we can start to see how this transporter can recognise a wide range of different cargo, allowing us to design better drugs that can enter our cells in the future. (Cryo-EM map and model from Nat Commun 14, 6374 (2023). https://doi.org/10.1038/s41467-023-42086-9).

Cryo-EM map of the human ether-a-go-go-related gene (hERG) potassium ion channel in traditional Chinese Shui-mo painting style.

This image was inspired from my research on the QacA multidrug efflux pump, found in the cell membrane of methicillin resistant Staphylococcus aureus. QacA is promiscuous and is able to efflux many quaternary ammonium compounds. Here, I used a combination of real scientific data from Molecular Dynamics simulations and an extrapolative approach to depict the dissociation of ethidium from the membrane embedded protein (unpublished).

The Gasdermin D pore perforates the plasma membrane to induce cell swelling and osmotic lysis during a form of programmed cell death called Pyroptosis. Gasdermin D pores release danger signals such as interleukins, triggering a response from the innate immune system to respond to areas of damage and infection. Upon cleavage by inflammatory caspases, the N-terminal domain of Gasdermin D oligomerises and forms ring-like structures and pores that disrupt cellular integrity causing eventual cell death. (Li et al Science (2024) http://doi.org/10.1126/science.adm9190)

A single cholesterol molecule (blue, metallic), floating in a lipid membrane (brightly coloured) binds to a specific site on the human Glycine Transporter GlyT2 (grey) to stabilise the binding of potential new painkillers. Unlike small molecule ligands, interactions between membrane lipids and proteins are noisy and chaotic, yet finding structural meaning in this liquid mess of interactions is essential to understand how membrane proteins and membrane lipids can regulate each other. (https://doi.org/10.1111/jnc.16028)

Depicted is the cryoEM structure of the Salmonella enterica Typhimurium flagellar motor-hook complex, as determined and described by Tan, Zhang, Wang, Xu, et al.; in the Structural basis of assembly and torque transmission of the bacterial flagellar motor, Cell (2021). The bacterial flagella is a supramolecular machine which is used to facilitate movement of bacterial cells. At the base of the flagella is the flagellar motor complex, which has components that rotate rapidly to facilitate the transmission of torque through to the joint region to the helical propellar, to propel the bacterial cell in a certain direction. PDB ID: 7CGO.

BALF2 is an annealase protein from Epstein-Barr Virus. It binds to independently generated single-stranded DNA overhangs and anneals them together, based on homology, within a helical annealing complex. We solved this structure by Cryo-EM.

SARS-CoV-2 spike protein binding to ACE2, cell surfaces not shown, with virus particles visible in the distance (PDB 8VKL).

A GPCR complexed with Gs proteins, showing as a charcoal sketch.