Structural and functional changes of surfactant protein A induced by ozone.
The major surfactant protein SP-A is thought to play an important role in the regulation of the structure and the metabolism of pulmonary surfactant. We investigated whether this protein may be a target in ozone toxicity. Several properties were studied that are probably relevant to the physiological functions of SP-A. In vitro exposure of human and canine SP-A to ozone led to decreases in 1) self-association of SP-A, 2) SP-A-mediated lipid aggregation, and 3) binding of SP-A to immobilized mannose. SP-A was neither degraded nor cross-linked by ozone exposure. Exposure of canine SP-A to ozone led to an increase in the apparent molecular weight of monomeric SP-A. Human SP-A did not show this change. Oxidation of methionine and tryptophan residues in canine SP-A was detected following ozone exposure. Reactions of ozone with other amino acid residues were not observed. The impairments of structure and properties of SP-A may contribute to the toxic action of ozone in the lungs.
Oosting
R S
RS
Laboratory of Veterinary Biochemistry, Utrecht University, The Netherlands.
van Greevenbroek
M M
MM
Verhoef
J
J
van Golde
L M
LM
Haagsman
H P
HP
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004285:Dogs; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008358:Mannose / Q000378:metabolism; D010126:Ozone / Q000494:pharmacology*; D010743:Phospholipids / Q000494:pharmacology; D011510:Proteolipids / Q000737:chemistry / Q000378:metabolism; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants / Q000737:chemistry / Q000378:metabolism; D013329:Structure-Activity Relationship
D010743:Phospholipids; D011510:Proteolipids; D037662:Pulmonary Surfactant-Associated Protein A; D037661:Pulmonary Surfactant-Associated Proteins; D011663:Pulmonary Surfactants; D010126:Ozone; D006861:Hydrogen Peroxide; D008358:Mannose; D002118:Calcium