A comparison of the copper sites in arthropod and mollusc oxyhemocyanins

Torensma, Ruurd; Phillips, J. C.

doi:10.1016/0014-5793(81)81147-7

Cited by 6 publications

(2 citation statements)

References 21 publications

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“…Amino acid sequence comparison with other arthropodan hemocyanins has shown that the subunits of the basic 450000-dalton hexamers are folded into three domain structures, with the central binuclear copper site located at the center of the second folded domain (Linzen et al, 1985). The studies of Gaykema et al (1984) and other spectroscopic investigations (Himmelwright et al, 1980;Torensma & Phillips, 1981; suggest that the basic 50000-dalton oxygen-binding center of the molluscan hemocyanins may have similar structural organization. The central folded domain together with the first or third domain in close contact may represent the basic molluscan globular unit, with eight such units forming each subunit of the hemocyanin (Brouwer et al, 1976;Siezen & Van Bruggen, 1974;Gielens et al, 1980).…”

Section: Discussionmentioning

confidence: 97%

Light-scattering investigation of the subunit structure and dissociation of Octopoda hemocyanins

Herskovits¹,

Villanueva²

1986

Biochemistry

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The molecular weights, subunit dissociation, and conformation in solution of the hemocyanins of three species of octopi were investigated by light-scattering, ultracentrifugation, absorbance, and circular dichroism methods. The molecular weights of the hemocyanins of Octopus bimaculoides, Octopus bimaculatus, and Octopus rubescens obtained by light scattering were 3.3 X 10(6), 3.4 X 10(6), and 3.5 (+/- 0.3) X 10(6), respectively. The average molecular weights of the fully dissociated hemocyanins of the same octopi, investigated at alkaline pH and in the presence of 8 M urea and 6 M guanidinium chloride (GdmCl), were found to be close to one-tenth of those of the parent proteins, with average molecular masses of 3.4 X 10(5), 3.3 X 10(5), and 3.3 (+/- 0.3) X 10(5). These findings confirm the earlier observations of van Holde and co-workers with other cephalopod hemocyanins that the basic cylindrical assembly of molluscan hemocyanins consists of 10 subunits. Circular dichroism and absorbance measurements suggest that the dissociated subunits at alkaline pH and in concentrated urea solutions retain their native, multidomain folding. Fairly concentrated GdmCl above 3-4 M is necessary to unfold fully the dissociated hemocyanin chains. Molecular weight measurements studied as a function of reagent concentration with the urea and Hofmeister salt series as dissociating agents show that the ureas are very effective dissociating agents, while the salts are ineffective to moderately effective reagents for octopus hemocyanin.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Discussionmentioning

confidence: 97%

Light-scattering investigation of the subunit structure and dissociation of Octopoda hemocyanins

Herskovits¹,

Villanueva²

1986

Biochemistry

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“…3) (Eccles, 1977;Brown et al, 1980;Co et al, 1981;Co & Hodgson, 1981). We have previously reported identical spectra for the oxy forms of mollusc and arthropod haemocyanins (Torensma & Phillips, 1981). This present paper deals with unexpected results of the analysis of the absorption edge structure not only from deoxy and oxy forms of haemocyanin but also of edges obtained at intermediate oxygenation values.…”

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confidence: 86%

Oxygen binding by Helix pomatia α-haemocyanin studied by X-ray-absorption spectroscopy

Torensma¹,

Phillips²

1983

Biochemical Journal

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The X-ray absorption spectra of haemocyanin from Helix pomatia were obtained by using X-rays from synchrotron radiation. Cu K-edges were recorded at four conditions, namely fully oxygenated, 85% oxygenated, 12% oxygenated and fully deoxygenated. The percentage oxygenation calculated from the edge-shift of the partially oxygenated samples did not agree with the percentage oxygenation as determined by u.v. measurements. Two intermediates in the oxygenation process are presented to explain the observed dissimilarities.

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Structure determination of Panulirus interruptus haemocyanin at 3.2 Å resolution

Gaykema

Volbeda

Hól

1986

Journal of Molecular Biology

130

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A comparison of the copper sites in arthropod and mollusc oxyhemocyanins

Cited by 6 publications

References 21 publications

Light-scattering investigation of the subunit structure and dissociation of Octopoda hemocyanins

Light-scattering investigation of the subunit structure and dissociation of Octopoda hemocyanins

Oxygen binding by Helix pomatia α-haemocyanin studied by X-ray-absorption spectroscopy

Structure determination of Panulirus interruptus haemocyanin at 3.2 Å resolution

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