Abstract
The effects of homopolymeric amino acids (molecular weight 2300 to 14,000) on the surface activity of dipalmitoyl phosphatidylcholine (DPPC) and DPPC/egg-phosphatidylglycerol (PG) were characterized by adsorption and dynamic surface tension lowering measurements at 37°C. Homopolyamino acids studied included polyl-leucine (poly-Leu) and poly-l-valine (poly-Val), since Leu and Val are known to be prominent in the structure of hydrophobic lung surfactant apoprotein SP-B and SP-C. In addition, several other homopolyamino acids with varying hydrophobicity index were also investigated, including poly-l-phenylalanine (poly-Phe), poly-l-serine (poly-Ser), poly-l-lysine (poly-Lys) and poly-l-glutamic acid (poly-Glu). Results showed that hydrophobic poly-Leu and poly-Phe at 1 and 10 weight percent greatly increased the adsorption facility of DPPC and DPPC/PG mixtures, with maximum surface pressures (up to 49 mN/m) near the equilibrium limit for phospholipid systems. In oscillating bubble studies, 1% mixture of poly-Leu or poly-Phe with DPPC or 8:2 DPPC/PG lowered surface tension into the range (near 1 mN/m) associated with active lung surfactant. In contrast, mixtures of DPPC and DPPC/PG with the more hydrophilic peptides poly-Ser, poly-Lys and poly-Glu showed little or no enhancement of surface activity over the phospholipids alone. Mixtures of poly-Val and phospholipids did not combine well with the simple co-sonication procedure used, and also exhibited little improvement in surface activity. Taken together, these results suggest that dydrophobicity is an important determinant for interactions of proteins with lung surfactant phospholipids, and that significant biophysical activity effects are not limited to highly specific amino acid sequences of the surfactant apoproteins, SP-B and SP-C. Simple homoamino acid polymers may provide useful model systems for investigating the specificity and character of some of these interactions, as well as the effectiveness of protein- phospholipidcombination in synthetic surfactant mixtures.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 157-164 |
| Number of pages | 8 |
| Journal | Chemistry and Physics of Lipids |
| Volume | 53 |
| Issue number | 2-3 |
| DOIs | |
| State | Published - 1990 |
| Externally published | Yes |
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Keywords
- dipalmitoyl phosphatidylcholine
- hydrophobic peptide
- lipid-protein interactions
- pulmonary surfactants
- surface adsorption
- surfactant apoproteins
ASJC Scopus subject areas
- Biochemistry
- Biophysics
Cite this
Hydrophobic homopolymeric peptides enhance the biophysical activity of synthetic lung phospholipids. / Venkitaraman, A. R.; Hall, Stephen (Steve); Notter, R. H.
In: Chemistry and Physics of Lipids, Vol. 53, No. 2-3, 1990, p. 157-164.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Hydrophobic homopolymeric peptides enhance the biophysical activity of synthetic lung phospholipids
AU - Venkitaraman, A. R.
AU - Hall, Stephen (Steve)
AU - Notter, R. H.
PY - 1990
Y1 - 1990
N2 - The effects of homopolymeric amino acids (molecular weight 2300 to 14,000) on the surface activity of dipalmitoyl phosphatidylcholine (DPPC) and DPPC/egg-phosphatidylglycerol (PG) were characterized by adsorption and dynamic surface tension lowering measurements at 37°C. Homopolyamino acids studied included polyl-leucine (poly-Leu) and poly-l-valine (poly-Val), since Leu and Val are known to be prominent in the structure of hydrophobic lung surfactant apoprotein SP-B and SP-C. In addition, several other homopolyamino acids with varying hydrophobicity index were also investigated, including poly-l-phenylalanine (poly-Phe), poly-l-serine (poly-Ser), poly-l-lysine (poly-Lys) and poly-l-glutamic acid (poly-Glu). Results showed that hydrophobic poly-Leu and poly-Phe at 1 and 10 weight percent greatly increased the adsorption facility of DPPC and DPPC/PG mixtures, with maximum surface pressures (up to 49 mN/m) near the equilibrium limit for phospholipid systems. In oscillating bubble studies, 1% mixture of poly-Leu or poly-Phe with DPPC or 8:2 DPPC/PG lowered surface tension into the range (near 1 mN/m) associated with active lung surfactant. In contrast, mixtures of DPPC and DPPC/PG with the more hydrophilic peptides poly-Ser, poly-Lys and poly-Glu showed little or no enhancement of surface activity over the phospholipids alone. Mixtures of poly-Val and phospholipids did not combine well with the simple co-sonication procedure used, and also exhibited little improvement in surface activity. Taken together, these results suggest that dydrophobicity is an important determinant for interactions of proteins with lung surfactant phospholipids, and that significant biophysical activity effects are not limited to highly specific amino acid sequences of the surfactant apoproteins, SP-B and SP-C. Simple homoamino acid polymers may provide useful model systems for investigating the specificity and character of some of these interactions, as well as the effectiveness of protein- phospholipidcombination in synthetic surfactant mixtures.
AB - The effects of homopolymeric amino acids (molecular weight 2300 to 14,000) on the surface activity of dipalmitoyl phosphatidylcholine (DPPC) and DPPC/egg-phosphatidylglycerol (PG) were characterized by adsorption and dynamic surface tension lowering measurements at 37°C. Homopolyamino acids studied included polyl-leucine (poly-Leu) and poly-l-valine (poly-Val), since Leu and Val are known to be prominent in the structure of hydrophobic lung surfactant apoprotein SP-B and SP-C. In addition, several other homopolyamino acids with varying hydrophobicity index were also investigated, including poly-l-phenylalanine (poly-Phe), poly-l-serine (poly-Ser), poly-l-lysine (poly-Lys) and poly-l-glutamic acid (poly-Glu). Results showed that hydrophobic poly-Leu and poly-Phe at 1 and 10 weight percent greatly increased the adsorption facility of DPPC and DPPC/PG mixtures, with maximum surface pressures (up to 49 mN/m) near the equilibrium limit for phospholipid systems. In oscillating bubble studies, 1% mixture of poly-Leu or poly-Phe with DPPC or 8:2 DPPC/PG lowered surface tension into the range (near 1 mN/m) associated with active lung surfactant. In contrast, mixtures of DPPC and DPPC/PG with the more hydrophilic peptides poly-Ser, poly-Lys and poly-Glu showed little or no enhancement of surface activity over the phospholipids alone. Mixtures of poly-Val and phospholipids did not combine well with the simple co-sonication procedure used, and also exhibited little improvement in surface activity. Taken together, these results suggest that dydrophobicity is an important determinant for interactions of proteins with lung surfactant phospholipids, and that significant biophysical activity effects are not limited to highly specific amino acid sequences of the surfactant apoproteins, SP-B and SP-C. Simple homoamino acid polymers may provide useful model systems for investigating the specificity and character of some of these interactions, as well as the effectiveness of protein- phospholipidcombination in synthetic surfactant mixtures.
KW - dipalmitoyl phosphatidylcholine
KW - hydrophobic peptide
KW - lipid-protein interactions
KW - pulmonary surfactants
KW - surface adsorption
KW - surfactant apoproteins
UR - http://www.scopus.com/inward/record.url?scp=0025214151&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0025214151&partnerID=8YFLogxK
U2 - 10.1016/0009-3084(90)90041-O
DO - 10.1016/0009-3084(90)90041-O
M3 - Article
C2 - 2337975
AN - SCOPUS:0025214151
VL - 53
SP - 157
EP - 164
JO - Chemistry and Physics of Lipids
JF - Chemistry and Physics of Lipids
SN - 0009-3084
IS - 2-3
ER -