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The structure of the giant haemoglobin from Glossoscolex paulistus

DOI: 10.1107/S1399004715005453 DOI Help
PMID: 26057666 PMID Help

Authors: José Fernando Ruggiero Bachega (Universidade de São Paulo) , Fernando Vasconcelos Maluf (Universidade de São Paulo) , Babak Andi (Brookhaven National Laboratory) , Humberto D'muniz Pereira (Universidade de São Paulo) , Marcelo Falsarella Carazzollea (Universidade Estadual de Campinas) , Allen M. Orville (Brookhaven National Laboratory) , Marcel Tabak (Universidade de São Paulo) , Jose Brandao-neto (Diamond Light Source) , Richard Charles Garratt (Universidade de São Paulo) , Eduardo Horjales Reboredo (Universidade de São Paulo)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acta Crystallographica Section D Biological Crystallography , VOL 71 (6) , PAGES 1257 - 1271

State: Published (Approved)
Published: June 2015

Abstract: The sequences of all seven polypeptide chains from the giant haemoglobin of the free-living earthworm Glossoscolex paulistus (HbGp) are reported together with the three-dimensional structure of the 3.6 MDa complex which they form. The refinement of the full particle, which has been solved at 3.2 Å resolution, the highest resolution reported to date for a hexagonal bilayer haemoglobin composed of 12 protomers, is reported. This has allowed a more detailed description of the contacts between subunits which are essential for particle stability. Interpretation of features in the electron-density maps suggests the presence of metal-binding sites (probably Zn2+ and Ca2+) and glycosylation sites, some of which have not been reported previously. The former appear to be important for the integrity of the particle. The crystal structure of the isolated d chain (d-HbGp) at 2.1 Å resolution shows different interchain contacts between d monomers compared with those observed in the full particle. Instead of forming trimers, as seen in the complex, the isolated d chains associate to form dimers across a crystallographic twofold axis. These observations eliminate the possibility that trimers form spontaneously in solution as intermediates during the formation of the dodecameric globin cap and contribute to understanding of the possible ways in which the particle self-assembles.

Journal Keywords: Erythrocruorins; Glossoscolex Paulistus; Giant Extracellular Haemoglobin; Hexagonal Bilayer.

Subject Areas: Biology and Bio-materials

Instruments: I04-1-Macromolecular Crystallography (fixed wavelength)