Abstract
Hemocyanins are oxygen carriers of arthropods and molluscs. The oxygen is bound between two copper ions, forming a Cu(II)-O2 2−-Cu(II) complex. The oxygenated active sites create two spectroscopic signals indicating the oxygen load of the hemocyanins: first, an absorption band at 340 nm which is due to a ligand-to-metal charge transfer complex, and second, a strong quenching of the intrinsic tryptophan fluorescence, the cause of which has not been definitively identified. We showed for the 4×6-mer hemocyanin of the tarantula Eurypelma californicum that the fluorescence quenching of oxygenated hemocyanin is caused exclusively by fluorescence resonance energy transfer (FRET). The tarantula hemocyanin consists of 24 subunits containing 148 tryptophans acting as donors and 24 active sites as acceptors. The donor–acceptor distances are determined on the basis of a closely related crystal structure of the horseshoe crab Limulus polyphemus hemocyanin subunit II (68–79% homology). Calculation of the expected fluorescence quenching and the measured transfer efficiency coincided extraordinary well, so that the fluorescence quenching of oxygenated tarantula hemocyanin can be completely explained by Förster transfer. This results explain for the first time, on a molecular basis, why fluorescence quantum yield can be used as an intrinsic signal for oxygen load of at least one arthropod hemocyanin, in particular that from the tarantula.
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References
Baldwin MJ, Root DE, Pate JE, Fujisawa K, Kitajima N, Solomon EI (1992) Spectroscopic studies of a side-on peroxide-bridged binuclear copper(II) model complex of relevance to the active sites in oxyhemocyanin and oxytyrosinase. J Am Chem Soc 114:10421–10431
Boteva R, Ricchelli F, Sartor G, Decker H (1993) Fluorescence properties of hamocyanin from tarantula (Eurypelma californicum): a comparison between the whole molecule and isolated subunits. J Photochem Photobiol B 17:145–153
Burmester T (2001) Molecular evolution of the arthropod hemocyanin superfamily. Mol Biol Evol 18:184–195
Callis PR (1997) 1La and 1Lb transitions of tryptophan: applications of theory and experimental observations to fluorescence of proteins. Methods Enzymol 278:113–150
Chen RF (1967) Fluorescence quantum yields of tryptophan and tyrosine. Anal Lett 1:35–42
Cuff ME, Miller KI, van Holde KE, Hendrickson WA (1998) Crystal structure of a functional unit from Octopus hemocyanin. J Mol Biol 278:855–870
Decker H, Hartmann H, Sterner R, Schwarz E, Pilz I (1996) Small-angle X-ray scattering reveals differences between the quaternary structures of oxygenated and deoxygenated tarantula hemocyanin. FEBS Lett 393:226–230
De Haas F, Van Bruggen EF (1994) The interhexameric contacts in the four-hexameric hemocyanin from the tarantula Eurypelma californicum. A tentative mechanism for cooperative behavior. J Mol Biol 237:464–478
Dewey TG, Hammes GG (1980) Calculation of fluorescence resonance energy transfer on surfaces. Biophys J 32:1023–1036
Dos Remedios CG, Moens PDJ (1995) Fluorescence resonance energy transfer spectroscopy is a reliable “ruler” for measuring structural changes in proteins. Dispelling the problem of the unknown orientation factor. J Struct Biol 115:175–185
Fairclough RH, Cantor CR (1978) The use of singlet-singlet energy transfer to study macromolecular assemblies. Methods Enzymol 48:347–379
Floyd JS, Haralampus-Grynaviski N, Ye T, Zheng B, Simon JD, Edington MD (2001) Time-resolved spectroscopic studies of radiationless decay processes in photoexcited hemocyanins. J Phys Chem B 105:1478–1483
Förster T (1948) Zwischenmolekulare energiewanderung und fluoreszenz. Ann Phys 2:55–75
Gaykema WPJ, Hol WGJ, Vereijken JM, Soeter NM, Bak HJ, Beintema JJ (1984) 3.2 Å structure of the copper-containing, oxygen-carrying protein Panulirus interruptus haemocyanin. Nature 309:23–29
Hartmann H, Decker H (2002) All hierarchical levels are involved in conformational transitions of the 4×6-meric tarantula hemocyanin upon oxygenation. Biochim Biophys Acta 1601:132–137
Hazes B, Magnus KA, Bonaventura C, Bonaventura J, Dauter Z, Kalk KH, Hol WGJ (1993) Crystal structure of deoxygenated Limulus polyphemus subunit II hemocyanin at 2.18 Å resolution: clues for a mechanism for allosteric regulation. Protein Sci 2:597–619
Kitajima N, Fujisawa K, Moro-oka Y (1989) µ-η2:η2-Peroxo binuclear copper complex, (Cu(HB(3,5-iPr2pz)3))2(O2). J Am Chem Soc 111:8975–8976
Kitajima N, Fujisawa K, Fujimoto C, Moro-oka Y, Hashimoto S, Kitagawa T, Toriumi K, Tatsumi K, Nakamura A (1992) A new model for dioxygen binding in hemocyanin: synthesis, characterization, and molecular structure of the µ-η2:η2-peroxo dinuclear copper(II) complexes (Cu(HB(3,5-R2pz)3))2(O2) (R=i-Pr and Ph). J Am Chem Soc 114:1277–1291
Lakowicz JR (1999) Principles of fluorescence spectroscopy, 2nd edn. Kluwer/Plenum, New York
Linzen B, Soeter NM, Riggs AF, Schneider HJ, Schartau W, Moore MD, Yokota E, Behrens PQ, Nakashima H, Takagi T, Nemoto T, Vereijken JM, Bak HJ, Beintema JJ, Volbeda A, Gaykema WPJ, Hol WGJ (1985) The structure of arthropod hemocyanins. Science 229:519–524
Loewe R (1978) Hemocyanins in spiders V: fluorimetric recording of oxygen binding curves, and its application to the analysis of allosteric interactions in Eurypelma californicum hemocyanin. J Comp Physiol 128:161–168
Magnus KA, Hazes B, Ton-That H, Bonaventura C, Bonaventura J, Hol WG (1994) Crystallographic analysis of oxygenated and deoxygenated states of arthropod hemocyanin shows unusual differences. Proteins 19:302–309
Markl J, Decker H (1992) Molecular structure of the arthropod hemocyanins. Adv Comp Environ Physiol 13:325–375
Markl J, Kempter B, Linzen B, Bijholt MMC, Van Bruggen EFJ (1981) Hemocyanins in spiders, XVI[1]. Subunit topography and a model of the quaternary structure of Eurypelma hemocyanin. Hoppe Seylers Z Physiol Chem 362:1631–1641
Perbandt M, Guthohrlein E W, Rypniewski W, Idakieva K, Stoeva S, Voelter W, Genov N, Betzel C (2003) The structure of a functional unit from the wall of a gastropod hemocyanin offers a possible mechanism for cooperativity. Biochemistry 42:6341–6346
Ricchelli F, Beltramini M, Flamigni L, Salvato B (1987) Emission quenching mechanisms in Octopus vulgaris hemocyanin: steady state and time-resolved fluorescence studies. Biochemistry 26:6933–6939
Richey B, Decker H, Gill SJ (1983) A direct test of the linearity between optical density change and oxygen binding in hemocyanins. In: Wood EJ (ed) Life chemistry reports: supplement 1. Harwood, New York, pp 309–312
Salvato B, Beltramini M (1987) Hemocyanins: molecular structure and reactivity of the binuclear copper site. Life Chem Rep 5:249–275
Salvato B, Beltramini M (1990) Hemocyanins: molecular architecture, structure and reactivity of the binuclear copper active site. Life Chem Rep 8:1–47
Savel-Niemann A, Markl J, Linzen B (1988) Hemocyanins in spiders. XXII. Range of allosteric interaction in a four-hexamer hemocyanin. Co-operativity and Bohr effect in dissociation intermediates. J Mol Biol 204:385–395
Shaklai N, Daniel E (1970) Fluorescence properties of hemocyanin from Levantina hierosolima. Biochemistry 9:564–568
Shaklai N, Daniel E (1972) Phosphorescence properties of hemocyanin from Levantina hierosolima. Biochemistry 11:2199–2203
Stryer L (1978) Fluorescence energy transfer as a spectroscopic ruler. Annu Rev Biochem 47:819–846
Van der Meer BW, Coker G, Chen SYS (1994) Resonance energy transfer. VCH, New York
Van Heel M, Dube P (1994) Quaternary structure of multihexameric arthropod hemocyanins. Micron 25:387–418
Van Holde KE, Miller KI (1995) Hemocyanins. Adv Protein Chem 47:1–81
Van Holde KE, Miller KI, Decker H (2001) Hemocyanins and invertebrate evolution. J Biol Chem 276:15563–15566
Voit R, Feldmaier-Fuchs G, Schweikardt T, Decker H, Burmester T (2000) Complete sequence of the 24-mer hemocyanin of the tarantula Eurypelma californicum. Structure and intramolecular evolution of the subunits. J Biol Chem 275:39339–39344
Volbeda A, Hol WG (1989) Crystal structure of hexameric haemocyanin from Panulirus interruptus refined at 3.2 Å resolution. J Mol Biol 209:249–279
Acknowledgements
We thank Hermann Hartmann for instructive discussions and the Deutsche Forschungsgemeinschaft (DFG) for financial support.
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Erker, W., Hübler, R. & Decker, H. Structure-based calculation of multi-donor multi-acceptor fluorescence resonance energy transfer in the 4×6-mer tarantula hemocyanin. Eur Biophys J 33, 386–395 (2004). https://doi.org/10.1007/s00249-003-0371-2
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DOI: https://doi.org/10.1007/s00249-003-0371-2