This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
2o8v
From Proteopedia
OCA (Talk | contribs)
(New page: 200px<br /><applet load="2o8v" size="450" color="white" frame="true" align="right" spinBox="true" caption="2o8v, resolution 3.000Å" /> '''PAPS reductase in a...)
Next diff →
Revision as of 10:58, 21 November 2007
|
PAPS reductase in a covalent complex with thioredoxin C35A
Overview
The crystal structure of Escherichia coli, 3'-phosphoadenosine-5'-phosphosulfate (PAPS) reductase in complex with E., coli thioredoxin 1 (Trx1) has been determined to 3.0 A resolution. The two, proteins are covalently linked via a mixed disulfide that forms during, nucleophilic attack of Trx's N-terminal cysteine on the Sgamma atom of the, PAPS reductase S-sulfocysteine (E-Cys-Sgamma-SO3-), a central intermediate, in the catalytic cycle. For the first time in a crystal structure, residues 235-244 in the PAPS reductase C-terminus are observed, depicting, an array of interprotein salt bridges between Trx and the strictly, conserved glutathione-like sequence, Glu238Cys239Gly240Leu241His242. The, structure also reveals a Trx-binding surface adjacent to the active site, cleft and regions of PAPS reductase associated with conformational change., Interaction at this site strategically positions Trx to bind the, S-sulfated C-terminus and addresses the mechanism for requisite structural, rearrangement of this domain. An apparent sulfite-binding pocket at the, protein-protein interface explicitly orients the S-sulfocysteine Sgamma, atom for nucleophilic attack in a subsequent step. Taken together, the, structure of PAPS reductase in complex with Trx highlights the large, structural rearrangement required to accomplish sulfonucleotide reduction, and suggests a role for Trx in catalysis beyond the paradigm of disulfide, reduction.
About this Structure
2O8V is a Protein complex structure of sequences from Escherichia coli. Active as Phosphoadenylyl-sulfate reductase (thioredoxin), with EC number 1.8.4.8 Full crystallographic information is available from OCA.
Reference
3'-Phosphoadenosine-5'-phosphosulfate Reductase in Complex with Thioredoxin: A Structural Snapshot in the Catalytic Cycle(,)., Chartron J, Shiau C, Stout CD, Carroll KS, Biochemistry. 2007 Apr 3;46(13):3942-3951. Epub 2007 Mar 13. PMID:17352498
Page seeded by OCA on Wed Nov 21 13:05:22 2007
