Sandbox Reserved 338: Difference between revisions
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{{STRUCTURE_2vnc | PDB=2vnc | SCENE=Sandbox_Reserved_338/2vnc/1}} | {{STRUCTURE_2vnc | PDB=2vnc | SCENE=Sandbox_Reserved_338/2vnc/1}} | ||
A debranching enzyme is responsible for the breakdown of glycogen <ref name="Woo"> PMID:18703518 </ref>. | ==Introduction== | ||
A debranching enzyme is responsible for the breakdown of glycogen <ref name="Woo">PMID: 18703518 </ref>. There are two main groups of debranching enzymes, and they are separated according to their activity <ref name="Woo" />. The first group, consists of pullulanases and isoamylases which only exhibit α-1,6-glycosidase activity <ref name="Woo" />. Whereas the second group consists of glycogen debranching enzymes which possess two functions; both α-1,6-glycosidase and α-1,4-transferase activity <ref name="Woo" />. | |||
TreX is an archaeal glycogen debranching enzyme from the species, ''Sulfolobus solfataricus'' <ref name="Woo" />. Even though TreX exhibits 74% sequence similarity to the isoamylase from ''Sulfolobus acidocaldarium'', TreX itself exhibits both α-1,6-glycosidase and α-1,4-transferase activity <ref name="Woo" />. It functions to debranch the side chains of glycogen into maltodextrin, and subsequently TreY and TreZ convert the maltodextrin into trehalose <ref name="Woo" /> <ref name="Park"> doi:10.1080/10242420701806652 </ref>. TreX can be found in two oligomeric states, either as a dimer or as a tetramer. As TreX is an oligomer, each conformational state exhibits a different catalytic activity <ref name="Woo" />. | |||
there is a glutamate residue, <scene name='Sandbox_Reserved_338/2vnc/3'>residue 100</scene> that I am interested in showing. | there is a glutamate residue, <scene name='Sandbox_Reserved_338/2vnc/3'>residue 100</scene> that I am interested in showing. | ||
==Structure and Function== | |||
TreX is an oligomer, as it exists in a dimeric state and a tetrameric state, both of which are active in solution <ref name="Woo" />. All subunits are identical, where the monomer contains 612 amino acids in total <ref name="Woo" />. The polypeptide folds into two secondary structures, a β-sandwhich in the N terminal region, comprised of six β-strands and a (β/α)8 – barrel motif in the central domain, comprised of eight parallel α-strands which encircle eight parallel β-strands <ref name="Woo" />. The sequence composition of the TreX monomer exhibits a high degree of homology to the isoamylase debranching enzyme of Pseudomona, however the TreX monomer mainly deviates from this similarity in its substrate binding groove and the absence of a calcium ion ligand <ref name="Woo" />. | |||
In the dimeric form, the individual subunits are adjacent to each other, where both of the active sites face the same side <ref name="Woo" />. In the tetrameric form, two of the associated dimers face each other so as to position the active sites on the inside of the tetramer <ref name="Woo" />. | |||
More to come… | |||
==Mechanism== | |||
==References== | ==References== | ||
<references/> | <references/> | ||
