Analysis of oxygen affinity in aquatic amphibian; homology modelling of the major Haemoglobin component HbA1 from the African clawed frog (Xenopus laevis, Anura)

Abstract

The homology model of major haemoglobin component HbA1 of the African Clawed Frog was predicted using the pigeon (Columba livia) haemoglobin as a template. The model was built with the help of MODELLER9v8. The models were evaluated with ProSA and PROCHECK. In X. laevis Gln38α is unable to form a hydrogen bond with β97His or β99Asp, which is responsible for the increase in oxygen affinity of the Xenopus HbA1. The hydrogen bond between α34Thr and β124Pro, which stabilises the deoxy state of the haemoglobin, was absent in X. laevis. Hence it is predicted that the HbA1 component of X. laevis has higher oxygen affinity.