RESUMO
Haemocyanins (Hcs) are copper-containing, respiratory proteins that occur in the haemolymph of many arthropod species. Here, we report the presence of Hcs in the chilopode Myriapoda, demonstrating that these proteins are more widespread among the Arthropoda than previously thought. The analysis of transcriptome of S. subspinipes subpinipes reveals the presence of two distinct subunits of Hc, where the signal peptide is present, and six of prophenoloxidase (PPO), where the signal peptide is absent, in the 75 kDa range. Size exclusion chromatography profiles indicate different quaternary organization for Hc of both species, which was corroborated by TEM analysis: S. viridicornis Hc is a 6 × 6-mer and S. subspinipes Hc is a 3 × 6-mer, which resembles the half-structure of the 6 × 6-mer but also includes the presence of phenoloxidases, since the 1 × 6-mer quaternary organization is commonly associated with hexamers of PPO. Studies with Chelicerata showed that PPO activity are exclusively associated with the Hcs. This study indicates that Scolopendra may have different proteins playing oxygen transport (Hc) and PO function, both following the hexameric oligomerization observed in Hcs.
Assuntos
Catecol Oxidase/metabolismo , Quilópodes/metabolismo , Precursores Enzimáticos/metabolismo , Hemocianinas/química , Hemocianinas/metabolismo , Análise de Sequência de DNA/métodos , Animais , Proteínas de Artrópodes/química , Proteínas de Artrópodes/genética , Proteínas de Artrópodes/metabolismo , Catecol Oxidase/química , Quilópodes/genética , Cromatografia em Gel , Precursores Enzimáticos/química , Regulação da Expressão Gênica , Hemocianinas/genética , Hemolinfa/metabolismo , Modelos Moleculares , Peso Molecular , Filogenia , Conformação Proteica , Multimerização ProteicaRESUMO
Haemocyanins (Hcs) are copper-containing, respiratory proteins that occur in the haemolymph of many arthropod species. Here, we report the presence of Hcs in the chilopode Myriapoda, demonstrating that these proteins are more widespread among the Arthropoda than previously thought. The analysis of transcriptome of S. subspinipes subpinipes reveals the presence of two distinct subunits of Hc, where the signal peptide is present, and six of prophenoloxidase (PPO), where the signal peptide is absent, in the 75 kDa range. Size exclusion chromatography profiles indicate different quaternary organization for Hc of both species, which was corroborated by TEM analysis: S. viridicornis Hc is a 6 × 6-mer and S. subspinipes Hc is a 3 × 6-mer, which resembles the half-structure of the 6 × 6-mer but also includes the presence of phenoloxidases, since the 1 × 6-mer quaternary organization is commonly associated with hexamers of PPO. Studies with Chelicerata showed that PPO activity are exclusively associated with the Hcs. This study indicates that Scolopendra may have different proteins playing oxygen transport (Hc) and PO function, both following the hexameric oligomerization observed in Hcs.
RESUMO
Haemocyanins (Hcs) are copper-containing, respiratory proteins that occur in the haemolymph of many arthropod species. Here, we report the presence of Hcs in the chilopode Myriapoda, demonstrating that these proteins are more widespread among the Arthropoda than previously thought. The analysis of transcriptome of S. subspinipes subpinipes reveals the presence of two distinct subunits of Hc, where the signal peptide is present, and six of prophenoloxidase (PPO), where the signal peptide is absent, in the 75 kDa range. Size exclusion chromatography profiles indicate different quaternary organization for Hc of both species, which was corroborated by TEM analysis: S. viridicornis Hc is a 6 × 6-mer and S. subspinipes Hc is a 3 × 6-mer, which resembles the half-structure of the 6 × 6-mer but also includes the presence of phenoloxidases, since the 1 × 6-mer quaternary organization is commonly associated with hexamers of PPO. Studies with Chelicerata showed that PPO activity are exclusively associated with the Hcs. This study indicates that Scolopendra may have different proteins playing oxygen transport (Hc) and PO function, both following the hexameric oligomerization observed in Hcs.
RESUMO
Thyroid hormone receptors (TR) play critical roles in virtually all tissues. The TR ligand-binding domain (LBD) participates in important activities, such as transcriptional activation and repression, through conformational changes induced by hormone binding. Two crystal forms of isoform alpha1 of the human thyroid hormone receptor LBD (hTRalpha1) in complex with the thyroid hormones T3 and Triac were obtained. The hTRalpha1-T3 complex was crystallized in a previously unobserved crystal form (space group P2(1)2(1)2(1), a = 59.98, b = 80.80, c = 102.21 A), with diffraction patterns extending to 1.90 A resolution on a rotating-anode X-ray source, and in space group C2 (a = 117.54, b = 80.66, c = 62.55 A, beta = 121.04 degrees), with data extending to 2.32 A resolution. The hTRalpha1-Triac complex was also crystallized in the new space group P2(1)2(1)2(1), with unit-cell parameters a = 60.01, b = 80.82, c = 102.39 A; its resolution limit extended to 2.20 A on a home source. Phasing was carried out by the molecular-replacement method and structural refinement is currently in progress. The refined structures may provide insight into the design of new thyromimetics.
