Structural comparison of recombinant pulmonary surfactant protein SP-A derived from two human coding sequences: implications for the chain composition of natural human SP-A.
The pulmonary surfactant-associated protein SP-A is encoded by presumably two different genes, resulting in slightly different amino acid sequences. Both gene products were expressed in Chinese hamster ovary cells. Their macromolecular structure differed significantly. SP-A alpha 3 exhibited a much higher amount of tetrameric to hexameric structures than SP-A alpha 2, for which dimeric structures predominate. These differences may be caused by the higher expression rates of SP-A alpha 3 presumably due to the presence of introns in the sequence. The occurrence of irregular disulfide links between individual oligomeric SP-A molecules composed of alpha 3-chains together with the demonstrated presence of both gene products in natural human SP-A suggest that the subunits of SP-A are heterotrimers of one alpha 2- and two alpha 3-chains.
Voss
T
T
Byk-Gulden Pharmazeutika, Department of Molecular Biology, Konstanz, Germany.
Melchers
K
K
Scheirle
G
G
Schäfer
K P
KP
D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D015139:Blotting, Southern; D002460:Cell Line; D004591:Electrophoresis, Polyacrylamide Gel; D005786:Gene Expression Regulation; D006801:Humans; D008969:Molecular Sequence Data; D011510:Proteolipids / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry; D012689:Sequence Homology, Nucleic Acid
D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D011994:Recombinant Proteins