Molecular cloning of a cDNA encoding the glycoprotein of hen oviduct microsomal signal peptidase.
Detergent-solubilized hen oviduct signal peptidase has been characterized previously as an apparent complex of a 19 kDa protein and a 23 kDa glycoprotein (GP23) [Baker & Lively (1987) Biochemistry 26, 8561-8567]. A cDNA clone encoding GP23 from a chicken oviduct lambda gt11 cDNA library has now been characterized. The cDNA encodes a protein of 180 amino acid residues with a single site for asparagine-linked glycosylation that has been directly identified by amino acid sequence analysis of a tryptic-digest peptide containing the glycosylated site. Immunoblot analysis reveals cross-reactivity with a dog pancreas protein. Comparison of the deduced amino acid sequence of GP23 with the 22/23 kDa glycoprotein of dog microsomal signal peptidase [Shelness, Kanwar & Blobel (1988) J. Biol. Chem. 263, 17063-17070], one of five proteins associated with this enzyme, reveals that the amino acid sequences are 90% identical. Thus the signal peptidase glycoprotein is as highly conserved as the sequences of cytochromes c and b from these same species and is likely to be found in a similar form in many, if not all, vertebrate species. The data also show conclusively that the dog and avian signal peptidases have at least one protein subunit in common.
Newsome
A L
AL
Department of Biochemistry, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC 27103.
McLean
J W
JW
Lively
M O
MO
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002645:Chickens; D003001:Cloning, Molecular; D003429:Cross Reactions; D004247:DNA / Q000235:genetics*; D004285:Dogs; D010450:Endopeptidases / Q000235:genetics*; D005260:Female; D006023:Glycoproteins / Q000235:genetics*; D008565:Membrane Proteins; D008861:Microsomes / Q000201:enzymology*; D008969:Molecular Sequence Data; D010057:Oviducts / Q000201:enzymology*; D012689:Sequence Homology, Nucleic Acid; D012697:Serine Endopeptidases
D006023:Glycoproteins; D008565:Membrane Proteins; D004247:DNA; D010450:Endopeptidases; D012697:Serine Endopeptidases; C026515:type I signal peptidase