1srx: Difference between revisions

[[Image:1srx.gif|left|200px]]<br /><applet load="1srx" size="350" color="white" frame="true" align="right" spinBox="true"  

The three-dimensional structure of the electron transport protein thioredoxin-S2 from E. coli has been determined from a 2.8 A resolution electron density map. The molecule is built up of a central core of three parallel and two antiparallel strands of pleated sheet surrounded by four helices. Thr residues involved in the active center 14-membered disulfide ring of thioredoxin form a protrusion between one of the helices and the middle strand of the pleated sheet. This region of the molecule, comprising two parallel strands joined by the protrusion and a helix, is structurally very similar to corresponding functionally important regions in the nucleotide-binding domains of flavodoxin and the dehydrogenases. The molecule has about 75% of the residues in well-defined secondary structures. The structure indicates that the carboxy-terminal third of the molecule forms an independent folding unit consisting of two strands of antiparallel pleated sheet and a terminal alpha-helix. This agress with the noncovalent reconstitution experiments from thioredoxin peptide fragments. Thioredoxin is an example of a protein with the active center located on a protrusion rather than in a cleft, thus demonstrating the existence of male proteins.

1SRX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli_b Escherichia coli b]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SRX OCA].  

[[Category: Soderberg, B O.]]

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