Data/hora: 23/06/2024 14:20:51

Biblioteca(s): | Embrapa Agricultura Digital.
Data corrente: | 15/04/2004
Data da última atualização: | 04/04/2019
Autoria: | KUSER, P.; HALL, D. R.; HAW, M. L.; NEU, M.; EVANS, R. W.; LINDLEY, P. F.
Afiliação: | PAULA KUSER, University of London; DAVID R. HALL, CLRC Daresbury Laboratory; MEI LING HAW, University of London, King's College London; MARGARETE NEU, CLRC Daresbury Laboratory; ROBERT W EVANS, King's College London; PETER F. LINDLEY, University of London, CLRC Daresbury Laboratory.
Título: | The mechanism of iron uptake by transferrins: the X-ray structures of the 18 kDa NII domain fragment of duck ovotransferrin and its nitrilotriacetate complex.
Ano de publicação: | 2002
Fonte/Imprenta: | Acta Crystallographica Section D: Biological Crystallography, D58, part 5, p. 777-783, May 2002.
DOI: | https://doi.org/10.1107/S0907444902003724
Idioma: | Inglês
Conteúdo: | In a previous paper [Lindley et al. (1993), Acta Cryst. D49, 292-304], the X-ray structure analysis of the 18 kDa fragment of duck ovotransferrin, corresponding to the NII domain of the intact protein, was reported at a resolution of 2.3 Å. In this structure, the FeIII cation binds to two tyrosine residues and the synergistic carbonate anion in an identical manner to that found in the intact protein. However, the aspartate and histidine residues, normally involved in iron binding in transferrins, are absent in the fragment and it was not possible to unequivocally define what had replaced them. The electron density was tentatively assigned to be a mixture of peptides, presumably resulting from the proteolytic preparation of the fragment, binding to the iron through their amino and carboxylate termini. A more recent X-ray analysis of the fragment, from a different preparation, has resulted in a structure at 1.95 Å, in which glycine appears to be the predominant residue bound to the cation. In an alternative attempt to clarify the binding of iron to the 18 kDa fragment, the metal was removed by dialysis and replaced in the form of ferric nitrilotriacetate. Crystallization of this complex has resulted in an X-ray structure at 1.90 Å in which the FeIII is bound to the synergistic carbonate anion and only one tyrosine residue in a manner almost identical to the intact protein. The carboxylate groups and the tertiary amino group of the nitrilotriacetate occupy the remaining coordination sites. The second tyrosine residue, Tyr95, is not bound directly to the iron. The implication of these structures with respect to the mechanism of iron binding by the transferrins is addressed.
Palavras-Chave: | Análise da estrutura de raio-X; Complexo NTA; NTA complex; Ovotransferrin; Serum transferrin.
Thesagro: | Ferro.
Categoria do assunto: | --
Registro original: | Embrapa Agricultura Digital (CNPTIA)

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CNPTIA - (10214-1) - ADD - SP - PP -  -  - 2004.00005 - DES
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