Influence of iron binding in the structural stability and cellular internalization of bovine lactoferrin
Caroline Augusto Barros,
Daniel Sanches,
Carlos Alberto Marques de Carvalho,
Ronimara Aparecida Santos,
Theo Luiz Ferraz de Souza,
Vitor Luis Macena Leite,
Samir Pereira da Costa Campos,
Andréa Cheble de Oliveira,
Rafael Braga Gonçalves
Affiliations
Caroline Augusto Barros
Departamento de Bioquímica, Instituto Biomédico, Universidade Federal do Estado do Rio de Janeiro, 20211-040, Rio de Janeiro, RJ, Brazil
Daniel Sanches
Natural Sciences Department, Arts and Sciences Division, South Florida State College, 33825, Avon Park, FL, United States
Carlos Alberto Marques de Carvalho
Departamento de Patologia, Centro de Ciências Biológicas e da Saúde, Universidade do Estado do Pará, 66095-662, Belém, PA, Brazil
Ronimara Aparecida Santos
Departamento de Nutrição Básica e Experimental, Instituto de Nutrição, Universidade do Estado do Rio de Janeiro, 20550-900, Rio de Janeiro, RJ, Brazil
Theo Luiz Ferraz de Souza
Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, 21941-590, Rio de Janeiro, RJ, Brazil
Vitor Luis Macena Leite
Departamento de Bioquímica, Instituto Biomédico, Universidade Federal do Estado do Rio de Janeiro, 20211-040, Rio de Janeiro, RJ, Brazil
Samir Pereira da Costa Campos
Instituto de Bioquímica Médica Leopoldo de Meis, Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil
Andréa Cheble de Oliveira
Instituto de Bioquímica Médica Leopoldo de Meis, Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Universidade Federal do Rio de Janeiro, 21941-902, Rio de Janeiro, RJ, Brazil
Rafael Braga Gonçalves
Departamento de Bioquímica, Instituto Biomédico, Universidade Federal do Estado do Rio de Janeiro, 20211-040, Rio de Janeiro, RJ, Brazil; Corresponding author.
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.
