1OXY

CRYSTALLOGRAPHIC ANALYSIS OF OXYGENATED AND DEOXYGENATED STATES OF ARTHROPOD HEMOCYANIN SHOWS UNUSUAL DIFFERENCES

Summary for 1OXY

• Entry DOI: 10.2210/pdb1oxy/pdb
• Descriptor: HEMOCYANIN (SUBUNIT TYPE II), COPPER (II) ION, OXYGEN MOLECULE, ... (4 entities in total)
• Functional Keywords: oxygen transport, hemocyanin, copper protein
• Biological source: Limulus polyphemus (Atlantic horseshoe crab)
• Cellular location: Secreted, extracellular space: P04253
• Total number of polymer chains: 1
• Total formula weight: 72816.65

Authors

Ton-that, H.,Magnus, K. (deposition date: 1995-01-06, release date: 1995-02-27, Last modification date: 2024-11-13)

Primary citation

Magnus, K.A.,Hazes, B.,Ton-That, H.,Bonaventura, C.,Bonaventura, J.,Hol, W.G.
Crystallographic analysis of oxygenated and deoxygenated states of arthropod hemocyanin shows unusual differences.
Proteins, 19:302-309, 1994

PubMed Abstract: The X-ray structure of an oxygenated hemocyanin molecule, subunit II of Limulus polyphemus hemocyanin, was determined at 2.4 A resolution and refined to a crystallographic R-factor of 17.1%. The 73-kDa subunit crystallizes with the symmetry of the space group R32 with one subunit per asymmetric unit forming hexamers with 32 point group symmetry. Molecular oxygen is bound to a dinuclear copper center in the protein's second domain, symmetrically between and equidistant from the two copper atoms. The copper-copper distance in oxygenated Limulus hemocyanin is 3.6 +/- 0.2 A, which is surprisingly 1 A less than that seen previously in deoxygenated Limulus polyphemus subunit II hemocyanin (Hazes et al., Protein Sci. 2:597, 1993). Away from the oxygen binding sites, the tertiary and quaternary structures of oxygenated and deoxygenated Limulus subunit II hemocyanins are quite similar. A major difference in tertiary structures is seen, however, when the Limulus structures are compared with deoxygenated Panulirus interruptus hemocyanin (Volbeda, A., Hol, W.G.J.J. Mol. Biol. 209:249, 1989) where the position of domain 1 is rotated by 8 degrees with respect to domains 2 and 3. We postulate this rotation plays an important role in cooperativity and regulation of oxygen affinity in all arthropod hemocyanins.

PubMed: 7984626
DOI: 10.1002/prot.340190405

Experimental method

X-RAY DIFFRACTION (2.4 Å)