Secondary and tertiary structure aberration of alpha globin chain in haemoglobin Q-India disorder.

Hemoglobinopathies are important inherited disorders with considerable high prevalence in Asia. Hemoglobin Q-India is a hemoglobinopathy that was first identified in India. Hb Q-India is caused by the mutation GAC --> CAC at codon 64 of the alpha-1 globin gene. The correlation between this hemoglobinopathy and thalassemia was reported. Although primary structure of disorder Hb Q-India is well documented, the secondary and tertiary structures, which can help explain the pathogenesis of the Hb Q-India disorder is not known. In this study, amino acid sequence of human alpha globin was searched using ExPASY and used for further mutation to Hb Q-India disorder. The derived sequences, alpha globin chains in both normal and Hb Q-India disorder, were used for further investigation for secondary and tertiary structures. Modeling of these proteins for secondary and tertiary structures was done using the NNPREDICT server and CPHmodels 2.0 Server, respectively. In this study, the secondary and tertiary structures of human alpha globin chains of normal and hemoglobin Q-India disorder are calculated and presented. Based on this information, the main difference between the predicted alpha globin secondary structures of normal and Hb Q-India is an extra helix in the Hb Q-India. The predicted tertiary structure also supports this finding. The results from this study can be good data for further study on Hb Q-India disorder, which can bring to the further understanding on this hemoglobinopathy.