PMID- 3427118
OWN - NLM
STAT- MEDLINE
DCOM- 19880318
LR  - 20190613
IS  - 0006-2960 (Print)
IS  - 0006-2960 (Linking)
VI  - 26
IP  - 24
DP  - 1987 Dec 1
TI  - Divalent cation and hydrogen ion effects on the structure and surface activity of 
      pulmonary surfactant.
PG  - 7986-93
AB  - The structure and surface activity of the extracellular fraction of pulmonary 
      surfactant known as tubular myelin are Ca2+ dependent. Previous studies have 
      demonstrated surfactant-specific proteins with monomeric molecular weights of 
      28,000-36,000 (SP28-36) are associated with this fraction. In reassembled 
      lipoprotein mixtures, SP28-36 promotes the Ca2+-induced aggregation and surface 
      activity of surfactant lipids, but the detailed interactions between Ca2+, 
      SP28-36, and surfactant lipids have not been established. In this study, we 
      investigated the effect of various cations on the aggregation of surfactant lipid 
      liposomes in the presence of SP28-36. SP28-36 reduced the threshold ion 
      concentration for liposome aggregation from greater than 10 to 0.5 mM for Ca2+, 
      Ba2+, and Sr2+ but not Mg2+ or Mn2+. The liposome aggregation was reversed by 
      ethylenediaminetetraacetic acid and not associated with leakage of 
      carboxyfluorescein. SP28-36 promoted similar liposome aggregation at pH less than 
      5 in the absence of divalent cations. Surfactant lipids adsorbed slowly to an 
      air-fluid interface in all ionic conditions unless SP28-36 was present. Both Ca2+ 
      and H+ induced rapid lipid adsorption in the presence of SP28-36. The surface 
      activity of native surfactant had a similar ion dependence. Electron micrographs 
      of native surfactant showed typical tubular myelin structures at pH 7.4 only in 
      the presence of Ca2+. At pH 4.4 in the absence of Ca2+, similar but not identical 
      structures were seen. In the reconstituted system, SP28-36 in the presence of 
      Ca2+ induced the formation of larger multilayered structures including parallel 
      bilayers and small areas of squares and triangles with dimensions similar to 
      structures found in the native material.(ABSTRACT TRUNCATED AT 250 WORDS)
FAU - Efrati, H
AU  - Efrati H
AD  - Department of Pediatrics, University of California, San Francisco 94143.
FAU - Hawgood, S
AU  - Hawgood S
FAU - Williams, M C
AU  - Williams MC
FAU - Hong, K
AU  - Hong K
FAU - Benson, B J
AU  - Benson BJ
LA  - eng
GR  - HL-240075/HL/NHLBI NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Biochemistry
JT  - Biochemistry
JID - 0370623
RN  - 0 (Cations, Divalent)
RN  - 0 (Fluoresceins)
RN  - 0 (Lipoproteins)
RN  - 0 (Liposomes)
RN  - 0 (Pulmonary Surfactants)
RN  - SY7Q814VUP (Calcium)
SB  - IM
MH  - Animals
MH  - Calcium
MH  - Cations, Divalent
MH  - Dogs
MH  - Fluoresceins
MH  - Hydrogen-Ion Concentration
MH  - Kinetics
MH  - Lipoproteins/isolation & purification/metabolism
MH  - Liposomes
MH  - Microscopy, Electron
MH  - Nephelometry and Turbidimetry
MH  - Pulmonary Surfactants/isolation & purification/*metabolism
MH  - Surface Properties
EDAT- 1987/12/01 00:00
MHDA- 1987/12/01 00:01
CRDT- 1987/12/01 00:00
PHST- 1987/12/01 00:00 [pubmed]
PHST- 1987/12/01 00:01 [medline]
PHST- 1987/12/01 00:00 [entrez]
AID - 10.1021/bi00398a066 [doi]
PST - ppublish
SO  - Biochemistry. 1987 Dec 1;26(24):7986-93. doi: 10.1021/bi00398a066.