Abstract

Human glycodelin A (GdA) is a glycoprotein that is highly homologous to bovine beta-lactoglobulin A (beta-LgA) because the amino acid sequences are 50-60% identical. The structural characteristics of human GdA and beta-LgA were compared in water and 2-propanol/water solutions. Circular dichroism spectra reveal that in water the two proteins have a very similar beta-sheet secondary structure. In the presence of 2-propanol/water mixtures (up to 50% v/v) the alpha-helix structure of both proteins increases. A further increase in the alcohol percentage of the solvent (up to 80% v/v 2-propanol) causes the formation of a new folded tertiary structure containing mainly beta-sheet features. Synchrotron radiation small angle X-ray scattering indicates that, in a neutral pH aqueous solution, GdA is a dimer. Its radius of gyration value (Rg), 25.1+/-0.4 A, is greater than that of beta-LgA (21.1+/-0.3 A), probably because of the contribution of polysaccharides bound to Asn-28 and Asn-63 residues of GdA. Conversely, small angle X-ray scattering and gel permeation chromatography data on GdA in 2-propanol have revealed a massive aggregation of the protein. Study holds ProTherm entries: 23799, 23800 Extra Details: deltaG[2-propanol]=deltaGH2O-m[2-propanol] glycodelin, beta-Lactoglobulin, circular dichroism, small angle X-ray scattering, protein aggregation

Submission Details

ID: Mn69Jrnb

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:54 p.m.

Version: 1

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