Applied Bioinformatics Course

Sequence, structure and function analysis the bar-headed goose hemoglobin

Hemoglobin is one of the most well studied proteins in the last century. The sequence, structure and function of several vertebrates have been investigated during the past 50 years. More than 200 hundreds of hemoglobin protein sequences have been deposited into the Swiss-Prot database. Three-dimensional structures wild type and mutants from dozens of species have been solved. This provides us a good opportunity to study the relationship among sequence, structure and function of hemoglobins.

Bar-headed goose is a special species of migration birds. They live in the Qinghai lake during summer time and fly to India all way along over the Tibetan plateau in autumn and come back in spring. Interestingly, close relative of bar-headed goose, the graylag goose lives in the low land of Indian all year around and do not migrate. Sequence alignment of bar-headed goose hemoglobin with that of graylag goose shows that there are only 4 substitutions. The Pro 119 in the alpha subunit of graylag goose has been changed to Ala in bar-headed goose. This residue is located in the surface of the alpha/beta interface. In 1983, Perutz proposed that this substitution reduces the contact between the alpha and beta subunit and increases the oxygen affinity, due to the relation of the tension status in the deoxy form (Perutz, 1983). During the past decade, a research group at Peking University has solved the crystal structure of both deoxy and oxy form of bar-headed goose, as well as the oxy form of the graylag goose hemoglobin (Zhang et al. 1996; Liang et al., 2001a; Liang et al., 2001b). We will use this example to learn how to analyze the sequence and structure of hemoglobin molecules.



Flying bar-headed goose Bar-headed goose on lake Bar-headed goose Greylag goose Bar-headed goose hemoglobin Bar-headed goose hemoglobin alpha119
The pictures of bar-headed goose and greylag goose were downloaded from several web pages. Thanks to the original authors to make these beautiful pictures available on the Internet.
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27 May 2017, J Luo, CBI, PKU, Beijing, China