X-ray Characterization of Conformational Changes of Human Apo- and Holo-Transferrin.
Int J Mol Sci
; 22(24)2021 Dec 13.
Article
em En
| MEDLINE
| ID: mdl-34948188
ABSTRACT
Human serum transferrin (Tf) is a bilobed glycoprotein whose function is to transport iron through receptor-mediated endocytosis. The mechanism for iron release is pH-dependent and involves conformational changes in the protein, thus making it an attractive system for possible biomedical applications. In this contribution, two powerful X-ray techniques, namely Macromolecular X-ray Crystallography (MX) and Small Angle X-ray Scattering (SAXS), were used to study the conformational changes of iron-free (apo) and iron-loaded (holo) transferrin in crystal and solution states, respectively, at three different pH values of physiological relevance. A crystallographic model of glycosylated apo-Tf was obtained at 3.0 Å resolution, which did not resolve further despite many efforts to improve crystal quality. In the solution, apo-Tf remained mostly globular in all the pH conditions tested; however, the co-existence of closed, partially open, and open conformations was observed for holo-Tf, which showed a more elongated and flexible shape overall.
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MEDLINE
Assunto principal:
Transferrina
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article