Octopus dofleini

Figure 2 Active sites of hemocyanins from horseshoe crab L. polyphemus (a oxy b deoxy), spiny lobster Panulirus interruptus (c), sweet potato Ipomoea batatas (d), Octopus dofleini (e), Rapana thomasiana (f). Cleary the four alpha-helix bundle motif with the metal center can be seen. The three histidines coordinating Cu-A are colored red, those coordinating Cu-B green. The two copper atoms are colored blue and oxygen red. The cysteines binding covalently a histidine at the Cu-A site are colored yellow. In the case of Ipomoea, a water molecule connects the two copper atoms...

Although the amino acid sequence of tyrosinase has only 25.3 and 26.0% identities with those of the /. batatas catechol oxidase and the odg domain of the Octopus dofleini hemocyanin, " respectively, its overall structure is quite similar to theirs. Among these three proteins, a high degree of conservation is observed in the core domain composed of the ct-bundle. The tyrosinase and hemocyanins from Panulirus interruputus and... 

Siuda, J.F., 1974. Chemical defence mechanisms of marine organisms. Identification of 8-hydroxy-4-quinolone from the ink of the giant octopus. Octopus dofleini Martini. Lloydia, 37 501—503. 

Hydroxy-4-Quinolone from the Ink of the Giant Octopus Octopus dofleini (Martin). Lloydia 37, 501-503 (1974). 

Molluscan hemocyanins. Two FUs from moUuscan hemocyanins were resolved, the oxy-form of O. dofleini He FU g (Figure 5b) and the deoxy-form of R. thomasiana He (Figure 5c ). Each FU consists of two domains. The N-terminal domain II carries the active site with a four alpha-helix bundle folding motif with two copper atoms. The C-terminal domain III replaces topologically the domain I in arthropod subunits and looks like a squeezed beta-barrel. Although the Rapana structure is not resolved as well as the Octopus FU, two different conformations can be deduced. In the oxy FU of Octopus hemocyanin, domain III covers the entrance to the active site completely while in the deoxy-form this domain is shifted a few degrees so that the channel to the active site becomes completely uncovered. 

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