User:Mina Schneider/Sandbox
From Proteopedia
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And its high level of conservation in species that diverged approximatively 80 million years ago, due to continental separation, suggests that the function of trichosurin is critical in metatherian lactation. | And its high level of conservation in species that diverged approximatively 80 million years ago, due to continental separation, suggests that the function of trichosurin is critical in metatherian lactation. | ||
| - | + | Lipocalins are a large family of ''extracellular'' proteins ''(17-25 kDa)'' that diverse in sequence but are structurally homologous. They bind and transport small hydrophobic molecules in a central hydrophobic pocket. The lipocalin family is defined by a common fold : an eight-stranded anti-parallel β-barrel with variable loop regions flanking and enclosing the top and bottom of the barrel, to form a hydrophobic pocket. | |
<Structure load='2r74' size='350' frame='true' align='right' caption='Trichosurin structure at pH 4.8' scene='Insert optional scene name here' /> | <Structure load='2r74' size='350' frame='true' align='right' caption='Trichosurin structure at pH 4.8' scene='Insert optional scene name here' /> | ||
Revision as of 18:33, 24 January 2017
Contents |
Trichosurin : a Possum Milk Whey Lipocalin Protein
The common brushtail possum (Trichosurus Vulpecula) belongs to the metatherians, a mammalian clade, which diverged from placental mammals (like humains) approximately 130 million years ago. It includes all mammals with an abdominal pouche. Indeed, metatherians have invested in lactation (secretion of milk from the mammary glands), as opposed to placentation, as a way of rearing their young. Reproduction in Trichosurus Vulpecula is typified by a short gestation (17 days) followed by a prolonged period of lactation (>200 days). Lactation is divided into at least 3 distinct phases between which milk composition changes dramatically (sources 1,6,7), going along with a unique biology of the early development of young opossum.
Trichosurin is one of the 3 predomiant lipocalins found in the milk of Trichosurus Vulpecula. And its high level of conservation in species that diverged approximatively 80 million years ago, due to continental separation, suggests that the function of trichosurin is critical in metatherian lactation.
Lipocalins are a large family of extracellular proteins (17-25 kDa) that diverse in sequence but are structurally homologous. They bind and transport small hydrophobic molecules in a central hydrophobic pocket. The lipocalin family is defined by a common fold : an eight-stranded anti-parallel β-barrel with variable loop regions flanking and enclosing the top and bottom of the barrel, to form a hydrophobic pocket.
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Fonction
In the lipocalin family, the internal topology of the hydrophobic pocket is a key factor to understand the type and the selectivity of binding. In fact, the access to the binding pocket is controlled by residues forming a loop between the β-strands at one end of the lipocalin β-barrel. Thus, the function of trichosurin is critical in metatherian lactation. But for the moment, the biochemical and biological functions of the trichosurin are not fully understood. Trichosurin may have a transporter activity for small molecules (http://www.uniprot.org/uniprot/Q29147).
Structural highlights
Forms a homodimer with four subunits.
This is a sample scene created with SAT to by Group, and another to make of the protein. You can make your own scenes on SAT starting from scratch or loading and editing one of these sample scenes.
</StructureSection>
References
Randall P. WATSON, Jerome DEMMER, Edward N. BAKER and Vickery L. ARCUS, "Three-dimensional structure and ligand binding properties of trichosurin, a metatherian lipocalin from the milk whey of the common brushtail possum Trichosurus vulpecula", Biochem. J. (2007) 408, 29–38
