Human hemoglobin, in your blood cells, displays precise changes in internal cooperativity in response to exactly how the first two oxygens bind to it. This video depicts, in dance, the study: "Resolving Pathways of Functional Coupling in Human Hemoglobin Using Quantitative Low Temperature Isoelectric Focusing of Asymmetric Mutant Hybrids" Hemoglobin is a 4-subunit protein (a tetramer) that binds and transports oxygen. Individual alpha-subunits and beta-subunits come together to form almost inseparable dimers (boy-girl pairs with matching eye-goggle and gloves in the dance). How dimer-1 interacts with dimer-2 in the whole protein, however, depends on the exact combination of bound oxygens (white balls). If one dimer gets 2 oxygens to itself, cooperativity is reduced and it does not interact well with the other dimer. If both dimers get at least 1 oxygen, they cooperate with each other, and usually bind 2 more oxygen molecules (for a total of 4). In normal hemoglobin, the two dimers are identical. Hemoglobin tetramers with two differing types of dimers are called "asymmetric mutant hybrids" (hence the different colored goggles and gloves on each "dance-mer"). "Low temperature isoelectric focusing" is a method that freezes (literally) and takes a snapshot of the dimer-dimer interactions at different times.

Mutations in P53 tumor suppressor are the commonest in human cancer. The protein controls various cellular processes such as DNA repair and apoptosis, and functions as the guardian against genomic instability. The three types of interactions are shown; sequence-specific DNA binding through the core region (1TUP.pdb, Gorina et al. Science vol. 265, 346), binding with 53BP1 BRCT domains (1GZH.pdb, Derbyshire et al. EMBOJ vol. 21, 3863) and a tetramer of the c-terminal oligomerization domain (1SAE.pdb, Clore et al. NatStrBio vol. 2, 321).

Self-assembly of a Functional Electronic Circuit Based on a Linear Mesoscale Tetramer. Solder droplets, selectively patterned on the faces of the blocks are employed to initiate, propagate and terminate the sequential alignment, registration, linking and electrical interconnection of each block. On contact, capillary interactions between the solder droplets cause the blocks to coalesce and self-assemble. Electrical characterisation following block assembly demonstrates the capillary force-based process successfully permits self-assembly and electrical interconnection of mesoscale blocks in a 1-D tetrameric format forming a functional electronic circuit.