Determining the glycation site specificity of human holo-transferrin.

Determining the glycation site specificity of human holo-transferrin. J Inorg Biochem. 2018 May 26;186:95-102 Authors: Silva AMN, Coimbra JTS, Castro MM, Oliveira Â, Brás NF, Fernandes PA, Ramos MJ, Rangel M Abstract Understanding the effect of glycation on the function of transferrin, the systemic iron transporter, is fundamental to fully grasp the mechanisms leading to the loss of iron homeostasis observed in diabetes mellitus (DM). The spontaneous reaction with protein amino groups is one of the main causes of glucose toxicity, but the site specificity of this reaction is still poorly understood. Here in, an in vitro approach was used to study human holo-transferrin glycation in detail. Lysine residues 103, 312 and 380 proved to be the most reactive sites, and overall glycation specificity was found to be remarkably different from that described for apo-transferrin. A computational biochemistry approach was subsequently applied to rationalize lysine reactivity. Even though pKa values, solvent accessible surface area, hydrogen bonds or the presence of nearby charged/polar residues could be related to lysine reactivity, these parameters do not suffice to describe glycation site specificity in holo-transferrin. Furthermore, analysis of the most reactive residues suggests that the correct lysine side chain orientation may play a fundamental role in reactivity. Nevertheless, in holo-transferrin, glycation occurs away from the iron-bi...
Source: Journal of Inorganic Biochemistry - Category: Biochemistry Authors: Tags: J Inorg Biochem Source Type: research