Structure
Structural biology has played a central role in the understanding of serpin function and biology. Over eighty serpin structures, in a variety of different conformations (described below), have been determined to date. Although the function of serpins varies widely, these molecules all share a common structure (or fold).
The structure of the non-inhibitory serpin ovalbumin, and the inhibitory serpin antitrypsin, revealed the archetype native serpin fold. All typically have three β-sheets (termed A, B and C) and eight or nine α-helices (hA-hI) (see figure 4). Serpins also possess an exposed region termed the reactive centre loop (RCL) that, in inhibitory molecules, includes the specificity determining region and forms the initial interaction with the target protease. In antitrypsin, the RCL is held at the top of the molecule and is not pre-inserted into the A β-sheet (figure 4, left panel). This conformation commonly exists in dynamic equilibrium with a partially inserted native conformation seen in other inhibitory serpins (see figure 4, right panel).
Read more about this topic: Serpin
Famous quotes containing the word structure:
“One theme links together these new proposals for family policy—the idea that the family is exceedingly durable. Changes in structure and function and individual roles are not to be confused with the collapse of the family. Families remain more important in the lives of children than other institutions. Family ties are stronger and more vital than many of us imagine in the perennial atmosphere of crisis surrounding the subject.”
—Joseph Featherstone (20th century)
“Who says that fictions only and false hair
Become a verse? Is there in truth no beauty?
Is all good structure in a winding stair?
May no lines pass, except they do their duty
Not to a true, but painted chair?”
—George Herbert (1593–1633)
“A committee is organic rather than mechanical in its nature: it is not a structure but a plant. It takes root and grows, it flowers, wilts, and dies, scattering the seed from which other committees will bloom in their turn.”
—C. Northcote Parkinson (1909–1993)