AMINO-ACID-SEQUENCE AND CRYSTAL-STRUCTURE OF BUFFALO ALPHA-LACTALBUMIN

Isolation, purification, amino acid sequence determination and X-ray c rystal structure of buffalo alpha-lactalbumin were performed in order to gain further knowledge of the molecular basis of alpha-lactalbumin in the lactose synthase complex. The deduced amino acid sequence diffe rs at one position from the bovine alpha-lactalbumin sequence (at posi tion 17). The refined crystal structure at 2.3 Angstrom is very simila r to those previously reported for human and baboon alpha-lactalbumins , However, a portion of the molecule (residues 105-109) exhibits diffe rent conformation. It forms a 'flexible loop', and appears to be a fun ctionally important region in forming the lactose synthase complex.