X-ray and primary structure of horse serum albumin (Equus caballus) at 0.27-nm resolution.
The amino-acid sequence and three-dimensional structure of equine serum albumin have been determined. The amino-acid sequence was deduced from cDNA isolated from equine liver. Comparisons of the primary structure of equine serum albumin with human serum albumin and bovine serum albumin reveal 76.1% and 73.9% sequence identity, respectively. The three-dimensional structure was determined crystallographically by the molecular-replacement method using molecular coordinates from the previously determined structure of human serum albumin, to a resolution of 0.27 nm. In accordance with the primary structure, the three-dimensional structures are highly conserved. There is a root-mean-square difference between alpha-carbons of the two structures of 0.201 nm. The association constants (Ka) for the binding of 2,3,5-triiodobenzoic acid were determined by ultrafiltration methods for equine and human serum albumins to be approximately 10(4) M-1 and 10(5) M-1, respectively. Crystallographic studies of equine serum albumin reveal two binding sites for 2,3,5-triiodobenzoic acid identical with those previously reported for human serum albumin which are located within subdomains in IIA and IIIA. Details and comparisons of the binding chemistry are discussed.
Ho
J X
JX
NASA, Marshall Space Flight Center, Huntsville, AL 35812.
Holowachuk
E W
EW
Norton
E J
EJ
Twigg
P D
PD
Carter
D C
DC
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003196:Computer Graphics; D006736:Horses; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D012709:Serum Albumin / Q000737:chemistry*; D014961:X-Ray Diffraction
D012709:Serum Albumin