Structure
RabGGTase is a heterodimer composed of alpha and beta subunits that are encoded by the RABGGTA and RABGGTB genes, respectively. The structure of rat RabGGTase has been determined by X-ray diffraction (see image to the left) to a resolution of 1.80 Å. RabGGTase’s secondary structure is largely composed of alpha helices; the alpha subunit is 74% helical with no beta sheets, while the beta subunit is 51% helical and 5% beta sheet. There are 28 alpha helices total (15 in the alpha subunit and 13 in the beta subunit) and 15 very short (no more than 4 residues) beta sheets. Functional RabGGTase binds three metal ions as ligands: two calcium ions (Ca2+) and a zinc ion (Zn2+), all of which interact with the beta subunit.
Read more about this topic: Rab Geranylgeranyltransferase
Famous quotes containing the word structure:
“The syntactic component of a grammar must specify, for each sentence, a deep structure that determines its semantic interpretation and a surface structure that determines its phonetic interpretation.”
—Noam Chomsky (b. 1928)
“Agnosticism is a perfectly respectable and tenable philosophical position; it is not dogmatic and makes no pronouncements about the ultimate truths of the universe. It remains open to evidence and persuasion; lacking faith, it nevertheless does not deride faith. Atheism, on the other hand, is as unyielding and dogmatic about religious belief as true believers are about heathens. It tries to use reason to demolish a structure that is not built upon reason.”
—Sydney J. Harris (1917–1986)
“If rightly made, a boat would be a sort of amphibious animal, a creature of two elements, related by one half its structure to some swift and shapely fish, and by the other to some strong-winged and graceful bird.”
—Henry David Thoreau (1817–1862)