cDNA cloning and sequencing of rat alpha 1-macroglobulin.
cDNA clones coding for the plasma protease inhibitor alpha 1-macroglobulin were isolated from a rat liver library. The obtained cDNA sequence contained 4701 nucleotides and had an open reading frame coding for a 1,500 amino acid long protein, including a 24 amino acid signal peptide. The identity of the deduced protein sequence as alpha 1-macroglobulin was established by comparison with published peptide sequences of the protein. The mature protein shares 53% and 57% overall amino acid identity with the two other identified members of the rat alpha-macroglobulin family, alpha 1-inhibitor 3 and alpha 2-macroglobulin. A sequence typical for an internal thiol ester was identified. Of the 24 cysteines, 23 are conserved with alpha 2-macroglobulin. However, instead of the two most C-terminal cysteines in alpha 2-macroglobulin, which forms a disulfide bridge in the receptor binding domain, alpha 1-macroglobulin contains phenylalanine. One mRNA species hybridizing with the alpha 1-macroglobulin probe was observed in rat and mouse liver RNA (approximately 6.2 kb), whereas no corresponding transcript was detected in RNA from human liver.
Department of Medical and Physiological Chemistry, Biomedical Center, Uppsala, Sweden.
B
B
Wärmegård
N
N
Martin
S
S
Johansson
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D004247:DNA / Q000737:chemistry* / Q000302:isolation & purification; D005353:Fibronectins / Q000235:genetics; D006801:Humans; D008099:Liver / Q000737:chemistry; D008969:Molecular Sequence Data; D051381:Rats; D017469:Receptors, Fibronectin; D011971:Receptors, Immunologic / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D000511:alpha-Macroglobulins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification
D005353:Fibronectins; D017469:Receptors, Fibronectin; D011971:Receptors, Immunologic; D000511:alpha-Macroglobulins; D004247:DNA