User:Sarah Abdalla/Thioredoxin Reductase: Difference between revisions

The functional unit of TR is a <scene name='User:Sarah_Abdalla/Thioredoxin_Reductase/Homodimer/2'>homodimer</scene>, typical of proteins in the family of glutathione reductases, with each subunit composed of mainly <scene name='User:Sarah_Abdalla/Thioredoxin_Reductase/Single_subunit/3'>alpha helices</scene> (<font color='yellow'>yellow</font>) and <scene name='User:Sarah_Abdalla/Thioredoxin_Reductase/Single_subunit/3'>β sheets</scene> (<font color='blue'>blue</font>).  Each monomer exhibits a three domain modular architecture, containing a NADP binding domain, a N-terminal FAD binding domain, and an interface domain. Both the <scene name='User:Sarah_Abdalla/Thioredoxin_Reductase/Homodimer/4'>FAD and NADP</scene> (in <font color='red'>red</font> and <font color='blue'>blue</font> respectively) binding domains have similar folds, and are variants of the [http://en.wikipedia.org/wiki/Rossman_fold Rossman Fold], characterized by a β sheet linked by several alpha helices which in the enzyme is composed of 5 strands surrounded by helices.  The two domains are positioned in a head to tail orientation allowing for electron transfer that leads to the reduction of the enzyme’s redox active center.  The <scene name='User:Sarah_Abdalla/Thioredoxin_Reductase/Active_site/1'>active site</scene> of the enzyme, characterized by the conserved Cys-Val-Asn-Val-Gly-Cys sequence, is located at the interface domain formed by two subunits, deeming the physiological significance of the dimeric form of the enzyme.  This domain is composed of a five stranded β sheet flanked on either side by two helices.  The C-terminal extension of TR runs parallel to the edge of the β sheet strand at the interface domain, with the last residues of the extension forming an arm that protrudes into the interface domain allowing for interaction with groups at the active site interface, which is located at the N-terminus <ref>PMID: 11481439</ref>. <applet load='2nvk' size='300' frame='true' align='right' caption='Insert caption here' />