MOLECULAR MECHANISM OF RESPIRATION IN HIGH ALTITUDE BIRDS: PRIMARY STRUCTURE AND HOMOLOGY MODELING OF HEMOGLOBIN COMPONENTS FROM COMMONCRANE(Grus grus; GRUIFORMES)
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Date
2010
Journal Title
Journal ISSN
Volume Title
Publisher
Center of Biotechnology
Abstract
The amino acid sequence of a “ and B-chains from the hemoglobin of Common crane
(Grus grus) has been determined. Common Crane belongs to the avian order Gruiformes,
family Gruidae. The gruidae is a small family with few species most of which are
endangered. The common crane is a migratory bird with long migratory route. It
migrates to Pakistan during winter from Western Siberia.
Separation of the hemoglobin polypeptide subunits was achieved by RP-HPLC. The
globin chains were digested by TCPK treated trypsin. The primary structure of the
hemoglobin was established by sequence determination of the tryptic peptides by
automatic Edman degradation on a gas-phase sequencer.
The hemoglobin of Common Crane is heterogeneous, having two hemoglobin
components, like all many other avian representatives. Position a34Cys and B44Ala are
unique amino acids present in common crane hemoglobin. Position, a8Ser, a55Val,
a64Gly, a67Val and B13Ser, B43Ser, B5S5Ile and B119Ala are specific to common crane
and are present in very few other avian hemoglobins sequenced so far. Homologous
comparison with the other avian species showed much conservation in the beta chain as
compared to alpha A chain. The automated homology model building was performed
using the protein structure modelling package, MODELLER9v7. The three dimensional
models of HbA oxy and deoxy were calculated using crystal structure coordinates of
Bar-headed goose [PDB id 1A4F (oxy), IHV4 (deoxy) hemoglobin. The various
exchanges atposition critical for structure and function of the hemoglobin are discussed.