Camelid α-lactalbumin is the only known protein that can undergo nonenzymatic deamidation on two Asn residues. This leads to the generation of a mixture of unusual isoAsp and D-Asp residues that may impact health.
The effect of deamidation on camel α-lactalbumin instability was investigated. Circular dichroism showed that the altered protein acquired secondary structure resulting in an increase in α-helix content. In good agreement,
the 3D structure of camel α-lactalbumin determined by X-ray crystallography, displayed a short additional α-helix probably induced by deamidation, compared to the human and bovine counterparts. This α-helix was located in the C-terminal region and included residues 101–106. Differential scanning calorimetry together with
the susceptibility to thermolysin showed that the deamidation process reinforced the structural stability of the α-lactalbumin at high temperature and its resistance toward proteolysis.