Panulirus Interruptus hemocyanin

N-linked carbohydrate chains from Panulirus interruptus hemocyanin [17,18]... 

More work on the combined application of XAS with ESR can be seen in the study of Panulirus interruptus hemocyanin in the crystalline state," straw lignin," and the hydrogen binding site in hydrogenase." ... 

The deoxy forms of hemocyanins are colorless, as a result of their 3d ° dicopper(I) centers. Although chemical and x-ray absorption spectroscopic studies had shed considerable light on the nature of the deoxy-He dicopper binding site, there now exist two x-ray crystal structures, the first on the the spiny lobster He, Panulirus interruptus [23], and a recent one of the horseshoe crab Limulus II protein [24], The structures exhibit rather different active-site characteristics, and since the former was crystallized at low pH and possesses rather odd copper coordination, the latter Limulus II structure is probably representative. It indicates that the two Cu(I) ions are 4.6 A apart, each found in a trigonal-planar coordination environment with Cu-NMs bond distances of about 2.0 A (Figure 1). Intersubunit 02 binding cooperative effects are probably initiated and trans-... 

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...

Hemocyanins are large, multisubunit dioxygen transporting proteins found in the hemolymph of many invertebrate species of the phyla of molluscs and arthropods 14). The subunits of molluscan hemocyanins contain functional units with a molecular weight of about 50,000 Da, each of which contains a dioxygen binding dicopper center. Arthropodal hemocyanins occur as hexamers, or multihexamers of subunits with a molecular weight of about 75,000 Da. As shown by the comparison of various X-ray crystal structures of the proteins from Panulirus interruptus (IS), Limulus polyphemus... 

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