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"SP-G", a putative new surfactant protein--tissue localization and 3D structure.

Rausch F, Schicht M, Paulsen F, Ngueya I, Bräuer L, Brandt W - PLoS ONE (2012)

Bottom Line: In this work, computational chemistry and molecular-biological methods were combined to localize and characterize SP-G.With the help of a protein structure model, specific antibodies were obtained which allowed the detection of SP-G not only on mRNA but also on protein level.This includes also the possibility of interactions with lipid systems and with that, a potential surface-regulatory feature of SP-G.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Halle, Germany.

ABSTRACT
Surfactant proteins (SP) are well known from human lung. These proteins assist the formation of a monolayer of surface-active phospholipids at the liquid-air interface of the alveolar lining, play a major role in lowering the surface tension of interfaces, and have functions in innate and adaptive immune defense. During recent years it became obvious that SPs are also part of other tissues and fluids such as tear fluid, gingiva, saliva, the nasolacrimal system, and kidney. Recently, a putative new surfactant protein (SFTA2 or SP-G) was identified, which has no sequence or structural identity to the already know surfactant proteins. In this work, computational chemistry and molecular-biological methods were combined to localize and characterize SP-G. With the help of a protein structure model, specific antibodies were obtained which allowed the detection of SP-G not only on mRNA but also on protein level. The localization of this protein in different human tissues, sequence based prediction tools for posttranslational modifications and molecular dynamic simulations reveal that SP-G has physicochemical properties similar to the already known surfactant proteins B and C. This includes also the possibility of interactions with lipid systems and with that, a potential surface-regulatory feature of SP-G. In conclusion, the results indicate SP-G as a new surfactant protein which represents an until now unknown surfactant protein class.

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Related in: MedlinePlus

Two sections of SP-G suggested as potentially useful antigen regions.The sections are highlighted on the protein structure model. Suggestion 1 in green comprises a short β-strand, suggestion 2 in red covers an α-helix on the protein surface.
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pone-0047789-g006: Two sections of SP-G suggested as potentially useful antigen regions.The sections are highlighted on the protein structure model. Suggestion 1 in green comprises a short β-strand, suggestion 2 in red covers an α-helix on the protein surface.

Mentions: The protein structure model was used to identify a peptide sequence with the most promising specific protein-antibody interaction. For that, the peptide sequence should be as unique as possible in the proteome, on the surface of the protein and without any predicted posttranslational modification. Two areas of the protein could be identified which fulfill these criteria by looking at the 3D-model (Figure 6). The first suggestion comprises a beta-strand of the amino acids 60 to 70 (GTSVTLHHARS). This section is rather short and contains only one arginine and two histidines which could interact considerably with an antibody. The rest of this sequence part contains mainly hydrophobic amino acids. For this reason, this peptide sequence was not considered as a potent antigen. The second suggestion covers an α-helix ranging from position 40 to 57 (YESSFLELLEKLCLLLHL). It contains not only a lysine and a histidine, but also three negatively charged glutamates. These residues are very likely to form ionic interactions or hydrogen bonds with an antibody. Only the second peptide sequence was suggested for the antibody production.


"SP-G", a putative new surfactant protein--tissue localization and 3D structure.

Rausch F, Schicht M, Paulsen F, Ngueya I, Bräuer L, Brandt W - PLoS ONE (2012)

Two sections of SP-G suggested as potentially useful antigen regions.The sections are highlighted on the protein structure model. Suggestion 1 in green comprises a short β-strand, suggestion 2 in red covers an α-helix on the protein surface.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3475697&req=5

pone-0047789-g006: Two sections of SP-G suggested as potentially useful antigen regions.The sections are highlighted on the protein structure model. Suggestion 1 in green comprises a short β-strand, suggestion 2 in red covers an α-helix on the protein surface.
Mentions: The protein structure model was used to identify a peptide sequence with the most promising specific protein-antibody interaction. For that, the peptide sequence should be as unique as possible in the proteome, on the surface of the protein and without any predicted posttranslational modification. Two areas of the protein could be identified which fulfill these criteria by looking at the 3D-model (Figure 6). The first suggestion comprises a beta-strand of the amino acids 60 to 70 (GTSVTLHHARS). This section is rather short and contains only one arginine and two histidines which could interact considerably with an antibody. The rest of this sequence part contains mainly hydrophobic amino acids. For this reason, this peptide sequence was not considered as a potent antigen. The second suggestion covers an α-helix ranging from position 40 to 57 (YESSFLELLEKLCLLLHL). It contains not only a lysine and a histidine, but also three negatively charged glutamates. These residues are very likely to form ionic interactions or hydrogen bonds with an antibody. Only the second peptide sequence was suggested for the antibody production.

Bottom Line: In this work, computational chemistry and molecular-biological methods were combined to localize and characterize SP-G.With the help of a protein structure model, specific antibodies were obtained which allowed the detection of SP-G not only on mRNA but also on protein level.This includes also the possibility of interactions with lipid systems and with that, a potential surface-regulatory feature of SP-G.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Halle, Germany.

ABSTRACT
Surfactant proteins (SP) are well known from human lung. These proteins assist the formation of a monolayer of surface-active phospholipids at the liquid-air interface of the alveolar lining, play a major role in lowering the surface tension of interfaces, and have functions in innate and adaptive immune defense. During recent years it became obvious that SPs are also part of other tissues and fluids such as tear fluid, gingiva, saliva, the nasolacrimal system, and kidney. Recently, a putative new surfactant protein (SFTA2 or SP-G) was identified, which has no sequence or structural identity to the already know surfactant proteins. In this work, computational chemistry and molecular-biological methods were combined to localize and characterize SP-G. With the help of a protein structure model, specific antibodies were obtained which allowed the detection of SP-G not only on mRNA but also on protein level. The localization of this protein in different human tissues, sequence based prediction tools for posttranslational modifications and molecular dynamic simulations reveal that SP-G has physicochemical properties similar to the already known surfactant proteins B and C. This includes also the possibility of interactions with lipid systems and with that, a potential surface-regulatory feature of SP-G. In conclusion, the results indicate SP-G as a new surfactant protein which represents an until now unknown surfactant protein class.

Show MeSH
Related in: MedlinePlus