1
|
Montandon GG, Cassoli JS, Peigneur S, Verano-Braga T, Santos DMD, Paiva ALB, Moraes ÉRD, Kushmerick C, Borges MH, Richardson M, Pimenta AMDC, Kjeldsen F, Diniz MRV, Tytgat J, Lima MED. GiTx1(β/κ-theraphotoxin-Gi1a), a novel toxin from the venom of Brazilian tarantula Grammostola iheringi (Mygalomorphae, Theraphosidae): Isolation, structural assessments and activity on voltage-gated ion channels. Biochimie 2020; 176:138-149. [PMID: 32717411 DOI: 10.1016/j.biochi.2020.07.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 06/30/2020] [Accepted: 07/08/2020] [Indexed: 12/14/2022]
Abstract
Spider venoms, despite their toxicity, represent rich sources of pharmacologically active compounds with biotechnological potential. However, in view of the large diversity of the spider species, the full potential of their venom molecules is still far from being known. In this work, we report the purification and structural and functional characterization of GiTx1 (β/κ-TRTX-Gi1a), the first toxin purified from the venom of the Brazilian tarantula spider Grammostola iheringi. GiTx1 was purified by chromatography, completely sequenced through automated Edman degradation and tandem mass spectrometry and its structure was predicted by molecular modeling. GiTx1 has a MW of 3.585 Da, with the following amino acid sequence: SCQKWMWTCDQKRPCCEDMVCKLWCKIIK. Pharmacological activity of GiTx1 was characterized by electrophysiology using whole-cell patch clamp on dorsal root ganglia neurons (DRG) and two-electrode voltage-clamp on voltage-gated sodium and potassium channels subtypes expressed in Xenopus laevis oocytes. GiTx1, at 2 μM, caused a partial block of inward (∼40%) and outward (∼20%) currents in DRG cells, blocked rNav1.2, rNav1.4 and mNav1.6 and had a significant effect on VdNav, an arachnid sodium channel isoform. IC50 values of 156.39 ± 14.90 nM for Nav1.6 and 124.05 ± 12.99 nM for VdNav, were obtained. In addition, this toxin was active on rKv4.3 and hERG potassium channels, but not Shaker IR or rKv2.1 potassium channels. In summary, GiTx1 is a promiscuous toxin with multiple effects on different types of ion channels.
Collapse
Affiliation(s)
- Gabriela Gontijo Montandon
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais - UFMG, Av. Antônio Carlos 6627, 31270-901, Belo Horizonte, MG, Brazil
| | - Juliana Silva Cassoli
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais - UFMG, Av. Antônio Carlos 6627, 31270-901, Belo Horizonte, MG, Brazil; Pharmacology and Toxicology, University of Leuven (KULeuven) - Campus Gasthuisberg, PO Box 922, Herestraat 49, 3000, Leuven, Belgium
| | - Steve Peigneur
- Pharmacology and Toxicology, University of Leuven (KULeuven) - Campus Gasthuisberg, PO Box 922, Herestraat 49, 3000, Leuven, Belgium
| | - Thiago Verano-Braga
- Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais - UFMG, Av. Antônio Carlos 6627, 31270-901, Belo Horizonte, MG, Brazil; Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Daniel Moreira Dos Santos
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais - UFMG, Av. Antônio Carlos 6627, 31270-901, Belo Horizonte, MG, Brazil
| | - Ana Luiza Bittencourt Paiva
- Diretoria de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias, Rua Conde Pereira Carneiro 80, 30510-010, Belo Horizonte, MG, Brazil
| | - Éder Ricardo de Moraes
- Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais - UFMG, Av. Antônio Carlos 6627, 31270-901, Belo Horizonte, MG, Brazil
| | - Christopher Kushmerick
- Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais - UFMG, Av. Antônio Carlos 6627, 31270-901, Belo Horizonte, MG, Brazil
| | - Márcia Helena Borges
- Diretoria de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias, Rua Conde Pereira Carneiro 80, 30510-010, Belo Horizonte, MG, Brazil
| | - Michael Richardson
- Diretoria de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias, Rua Conde Pereira Carneiro 80, 30510-010, Belo Horizonte, MG, Brazil
| | - Adriano Monteiro de Castro Pimenta
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais - UFMG, Av. Antônio Carlos 6627, 31270-901, Belo Horizonte, MG, Brazil
| | - Frank Kjeldsen
- Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Marcelo Ribeiro Vasconcelos Diniz
- Diretoria de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias, Rua Conde Pereira Carneiro 80, 30510-010, Belo Horizonte, MG, Brazil
| | - Jan Tytgat
- Pharmacology and Toxicology, University of Leuven (KULeuven) - Campus Gasthuisberg, PO Box 922, Herestraat 49, 3000, Leuven, Belgium
| | - Maria Elena de Lima
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais - UFMG, Av. Antônio Carlos 6627, 31270-901, Belo Horizonte, MG, Brazil; Santa Casa de Belo Horizonte, Instituto de Ensino e Pesquisa, Rua Domingos Vieira, 590, 30150-240, Belo Horizonte, MG, Brazil.
| |
Collapse
|
3
|
De La Mora-De La Mora I, Torres-Larios A, Mendoza-Hernández G, Enriquez-Flores S, Castillo-Villanueva A, Mendez ST, Garcia-Torres I, Torres-Arroyo A, Gómez-Manzo S, Marcial-Quino J, Oria-Hernández J, López-Velázquez G, Reyes-Vivas H. The E104D mutation increases the susceptibility of human triosephosphate isomerase to proteolysis. Asymmetric cleavage of the two monomers of the homodimeric enzyme. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:2702-11. [PMID: 24056040 DOI: 10.1016/j.bbapap.2013.08.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 08/26/2013] [Accepted: 08/27/2013] [Indexed: 11/27/2022]
Abstract
The deficiency of human triosephosphate isomerase (HsTIM) generates neurological alterations, cardiomyopathy and premature death. The mutation E104D is the most frequent cause of the disease. Although the wild type and mutant exhibit similar kinetic parameters, it has been shown that the E104D substitution induces perturbation of an interfacial water network that, in turn, reduces the association constant between subunits promoting enzyme inactivation. To gain further insight into the effects of the mutation on the structure, stability and function of the enzyme, we measured the sensitivity of recombinant E104D mutant and wild type HsTIM to limited proteolysis. The mutation increases the susceptibility to proteolysis as consequence of the loss of rigidity of its overall 3-D structure. Unexpectedly, it was observed that proteolysis of wild type HsTIM generated two different stable nicked dimers. One was formed in relatively short times of incubation with proteinase K; as shown by spectrometric and crystallographic data, it corresponded to a dimer containing a nicked monomer and an intact monomer. The formation of the other nicked species requires relatively long incubation times with proteinase K and corresponds to a dimer with two clipped subunits. The first species retains 50% of the original activity, whereas the second species is inactive. Collectively, we found that the E104D mutant is highly susceptible to proteolysis, which in all likelihood contributes to the pathogenesis of enzymopathy. In addition, the proteolysis data on wild type HsTIM illustrate an asymmetric conduct of the two monomers.
Collapse
|
4
|
Reyes-Vivas H, Martínez-Martínez E, Mendoza-Hernández G, López-Velázquez G, Pérez-Montfort R, Tuena de Gómez-Puyou M, Gómez-Puyou A. Susceptibility to proteolysis of triosephosphate isomerase from two pathogenic parasites: characterization of an enzyme with an intact and a nicked monomer. Proteins 2002; 48:580-90. [PMID: 12112681 DOI: 10.1002/prot.10179] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The susceptibility to subtilisin of homodimeric triosephosphate isomerase from Trypanosoma brucei (TbTIM) and Trypanosoma cruzi (TcTIM) was studied. Their amino sequence and 3D structure are markedly similar. In 36 h of incubation at a molar ratio of 4 TIM per subtilisin, TcTIM underwent extensive hydrolysis, loss of activity, and large structural alterations. Under the same conditions, only about 50% of the monomers of TbTIM were cleaved in two sites. The higher sensitivity of TcTIM to subtilisin is probably due to a higher intrinsic flexibility. We isolated and characterized TbTIM that had been exposed to subtilisin. It exhibited the molecular mass of the dimer, albeit it was formed by one intact and one nicked monomer. Its k(cat) with glyceraldehyde 3-phosphate was half that of native TbTIM, with no change in K(m). The intrinsic fluorescence of nicked TbTIM was red-shifted by 5 nm. The association between subunits was not affected. The TbTIM data suggest that there are structural differences in the two monomers or that alterations of one subunit change the characteristics of the other subunit. In comparison to the action of subtilisin on TIMs from other species, the trypanosomal enzymes appear to be unique.
Collapse
Affiliation(s)
- Horacio Reyes-Vivas
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de Mexico, Mexico.
| | | | | | | | | | | | | |
Collapse
|
9
|
Godfrey EW. Comparison of agrin-like proteins from the extracellular matrix of chicken kidney and muscle with neural agrin, a synapse organizing protein. Exp Cell Res 1991; 195:99-109. [PMID: 1647326 DOI: 10.1016/0014-4827(91)90504-n] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Agrin is a synapse-organizing protein that is concentrated in embryonic motor neurons and the synaptic basal lamina of the neuromuscular junction. Agrin or closely related proteins are also associated with most other basal laminae. Here I report that the major agrin-like proteins from the nervous system and other tissues of the chicken are immunochemically and biochemically similar. Four major agrin-like proteins of approximately 60, 72, 80, and 90 kDa were identified on immunoblots of agrin preparations from both neural and non-neural tissues. Agrin-like proteins from embryonic chicken brain and adult kidney were similar in amino acid composition. Rabbit antisera against each of the kidney proteins labeled basement membranes of several tissues, as well as spinal cord motor neurons. These antibodies specifically precipitated and inhibited acetylcholine receptor (AChR)-aggregating activity from the chicken nervous system and Torpedo electric organ. Thus, the agrin-like proteins of non-neural tissues in the chicken are closely related to agrin from the nervous system. However, the AChR-aggregating activity of chicken agrin preparations differed depending on the tissue of origin. Agrin enriched by immunoaffinity chromatography from the central nervous system induced large numbers of AChR aggregates on cultured myotubes. In contrast, agrin preparations from other chicken tissues induced dramatically fewer and smaller AChR aggregates. The difference in biological activity between these agrin preparations may reflect differential inactivation or the existence of tissue- or cell-specific isoforms of agrin.
Collapse
Affiliation(s)
- E W Godfrey
- Department of Cellular Biology and Anatomy, Medical College of Wisconsin, Milwaukee 53226
| |
Collapse
|
10
|
Duffort OA, Carreira J, Nitti G, Polo F, Lombardero M. Studies on the biochemical structure of the major cat allergen Felis domesticus I. Mol Immunol 1991; 28:301-9. [PMID: 1712068 DOI: 10.1016/0161-5890(91)90141-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The major cat allergen, Fel d I, was purified to homogeneity from cat dander extract by sequential mAb affinity chromatography and HPLC size exclusion. The purity and allergenic activity of the preparation was demonstrated by different techniques such as HPLC, RAST inhibition, skin prick tests and CIE/CRIE. Fel d I showed a mol. wt of about 35,000 by HPLC gel filtration and of 18,000 by SDS-PAGE, confirming that it is a non-covalently linked dimer. However, SDS-PAGE analysis under reducing conditions as well as labelling experiments with 14C-iodoacetamide of 2-ME-reduced Fel d I showed that each mol. wt 18,000 monomer is comprised of two covalently S-S bound polypeptides with apparent mol. wt. of 4000 (alpha-chain) and 14,000 (beta-chain). Reduction and alkylation of Fel d I obliterated most of its allergenic activity, as determined by RAST inhibition and immunoblotting, suggesting that most of the IgE-binding sites are conformational. On the other hand, treatment of Fel d I by N-glycanase under reducing and non-reducing conditions indicated the presence of N-linked oligosaccharides in the beta-chain. Carbohydrate analysis data of the whole Fel d I molecule showed the presence of a relatively high carbohydrate content (approximately 20%). RAST inhibition experiments of native and deglycosilated allergen suggest that most IgE epitopes are located in the protein moiety of the molecule. However, the deglycosilated allergen showed a 2-4 fold reduction in its inhibition capacity of RAST as compared to the native allergen, suggesting that carbohydrates could have some role in keeping the active conformation of those epitopes. The N-terminal amino acid sequence of the beta-chain (20 residues) and most of the alpha-chain (40 residues) were determined. Both chain sequences showed no homology with other known protein sequences.
Collapse
Affiliation(s)
- O A Duffort
- Departamento de Investigación, Algeria e Immunología Abelló S.A., Madrid, Spain
| | | | | | | | | |
Collapse
|
16
|
Simpson RJ, Ward LD, Reid GE, Batterham MP, Moritz RL. Peptide mapping and internal sequencing of proteins electroblotted from two-dimensional gels onto polyvinylidene difluoride membranes. A chromatographic procedure for separating proteins from detergents. J Chromatogr A 1989; 476:345-61. [PMID: 2777983 DOI: 10.1016/s0021-9673(01)93881-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Direct sequence analysis of proteins electroblotted from two-dimensional polyacrylamide gels onto immobilizing matrices provides an efficient technique for obtaining N-terminal sequence data for proteins not amenable to purification by reversed-phase high-performance liquid chromatography (RP-HPLC). We present in this paper a procedure for obtaining peptide fragments from electroblotted proteins for internal amino acid sequence analysis. First, Coomassie Blue-stained proteins are extracted from polydivinylidene difluoride membranes, using a detergent mixture of sodium dodecylsulfate and Triton X-100. Proteins are then separated from the detergent mixture by a chromatographic procedure which relies on the ability of proteins to interact with certain reversed-phase sorbents at high organic solvent concentrations. Under these conditions, detergents and Coomassie Blue are not retained and pass through the column. Proteins are recovered by simultaneously: (i) introducing trifluoroacetic acid into the mobile phase and (ii) decreasing the organic solvent concentration. After proteolytic fragmentation, peptides are purified by microbore-column (1-2 mm I.D.) RP-HPLC for microsequence analysis.
Collapse
Affiliation(s)
- R J Simpson
- Joint Protein Structure Laboratory, Ludwig Institute for Cancer Research (Melbourne Branch), Victoria, Australia
| | | | | | | | | |
Collapse
|