Sandbox8999: Difference between revisions
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Individual clathrin molecules can assemble into cage-like structures. When individual clathrin molecules come together, a lattice is formed where each lattice point is associated with the center of a triskelion (from the Greek word meaning “a three legged structure”).<ref name="harrison" /> According to Crowther, R.A., clathrin vesicles are constructed from 12 pentagonal units plus a number of hexagonal units, with the number of hexagons increasing for larger clathrin coats.<ref name="crowther">PMID: 7328122 </ref> The term “cage” can be used to refer to empty shells composed only of clathrin where “coat” refers to clathrin plus associated proteins and vesicles.<ref name="crowther" /> Clathrin lattices are formed under optimal conditions of physiological pH (6.0-6.5) and in the presence of Calcium or Magnesium ions.<ref name="crowther" /> Various packing models have been investigated as to how the individual triskelion legs assemble into clathrin cages.<ref name="crowther" /> As mentioned above, the center of the triskelion legs occurs at each vertex of the cage, meaning pentagons, heptagons, and hexagons can be formed.<ref name="crowther" /> In the individual triskelion legs, the bend in the leg is 160 Angstroms from the vertex, giving rise to two models of packing: simple side-by-side packing or a cross-over type of packing,<ref name="crowther" /> Cross-over packing occurs when a hexamer of triskelions are formed with crossing over of the leg portions of the triskelions.<ref name="crowther" /> Simple packing does not involve crossing over, but side by side packing of the leg portions of the triskelions.<ref name="crowther" /> | Individual clathrin molecules can assemble into cage-like structures. When individual clathrin molecules come together, a lattice is formed where each lattice point is associated with the center of a triskelion (from the Greek word meaning “a three legged structure”).<ref name="harrison" /> According to Crowther, R.A., clathrin vesicles are constructed from 12 pentagonal units plus a number of hexagonal units, with the number of hexagons increasing for larger clathrin coats.<ref name="crowther">PMID: 7328122 </ref> The term “cage” can be used to refer to empty shells composed only of clathrin where “coat” refers to clathrin plus associated proteins and vesicles.<ref name="crowther" /> Clathrin lattices are formed under optimal conditions of physiological pH (6.0-6.5) and in the presence of Calcium or Magnesium ions.<ref name="crowther" /> Various packing models have been investigated as to how the individual triskelion legs assemble into clathrin cages.<ref name="crowther" /> As mentioned above, the center of the triskelion legs occurs at each vertex of the cage, meaning pentagons, heptagons, and hexagons can be formed.<ref name="crowther" /> In the individual triskelion legs, the bend in the leg is 160 Angstroms from the vertex, giving rise to two models of packing: simple side-by-side packing or a cross-over type of packing,<ref name="crowther" /> Cross-over packing occurs when a hexamer of triskelions are formed with crossing over of the leg portions of the triskelions.<ref name="crowther" /> Simple packing does not involve crossing over, but side by side packing of the leg portions of the triskelions.<ref name="crowther" /> | ||
[[Image:LatticeStructure2.png |frame| Model | [[Image:LatticeStructure2.png |frame| Models of the various packing models of triskelion components of clathrin. Each vertex of the polygon is made of a triskelion and the legs of the triskelion run along the edges. (a) Simple side-by-side packing model of the legs in which there is no overlap and a hexamer is formed. (b) Model of cross-over packing of the triskelion legs forming a hexamer and (c) Similar model as (b) except a pentamer is formed by the triskelions with crossing over of the leg portions.<ref name="crowther" />]] | ||
== Function == | == Function == | ||
