Influence of iron binding in the structural stability and cellular internalization of bovine lactoferrin

Abstract

Lactoferrin (Lf) is an iron-binding glycoprotein and a component of many external secretions with a wide diversity of functions. Structural studies are important to understand the mechanisms employed by Lf to exert so varied functions. Here, we used guanidine hydrochloride and high hydrostatic pressure to cause perturbations in the structure of bovine Lf (bLf) in apo and holo (unsaturated and iron-saturated, respectively) forms, and analyzed conformational changes by intrinsic and extrinsic fluorescence spectroscopy. Our results showed that the iron binding promotes changes on tertiary structure of bLf and increases its structural stability. In addition, we evaluated the effects of bLf structural change on the kinetics of bLf internalization in Vero cells by confocal fluorescence microscopy, and observed that the holo form was faster than the apo form. This finding may indicate that structural changes promoted by iron binding may play a key role in the intracellular traffic of bLf. Altogether, our data improve the comprehension of bLf stability and uptake, adding knowledge to its potential use as a biopharmaceutical.

Bovine lactoferrin inhibits SARS‐CoV‐2 and SARS‐CoV‐1 by targeting the RdRp complex and alleviates viral infection in the hamster model

“…Based on the inhibitory effect of bLf on viral post‐entry at the cell culture level, we assumed that bLf also exerted its antiviral effect at the viral post‐entry stage by inhibiting viral replication. Lf has been endocytosed by several cell types, including Vero E6, Huh‐7, and Caco‐2 cells 34–36 . The internalization of Lf provides a prerequisite for its antiviral effect in cells.…”

“…Lf has been endocytosed by several cell types, including Vero E6, Huh‐7, and Caco‐2 cells. 34 , 35 , 36 The internalization of Lf provides a prerequisite for its antiviral effect in cells. RdRp and M pro /3CL pro protease play important roles in the replication and assembly of SARS‐CoV‐2, and both serve as ideal targets for developing antiviral drugs.…”

Bovine Lactoferrin Induces Cell Death in Human Prostate Cancer Cells

“…This work showed that the presence of the iron ion in the holo-bLf structure promotes changes in its tertiary structure, when evaluating the tryptophan microenvironments and the interaction with the extrinsic fluorescent probe bis-ANS. In addition, holo-bLf has shown to have greater structural stability against chemical and physical disruptors [34].…”

Iron transport mechanism of lactoferrin and its application in food processing

“…Besides, thermal processing induced LF to show a less compact protein structure in the new exposed regions of the surface, further to trigger the denaturation and aggregation (Goulding et al, 2021a). The binding of bLF to iron promotes changes in tertiary structure which increases its structural stability (Barros et al, 2021).…”