2O8V

PAPS reductase in a covalent complex with thioredoxin C35A

Summary for 2O8V

• Entry DOI: 10.2210/pdb2o8v/pdb
• Related: 1SUR 2TRX
• Descriptor: Phosphoadenosine phosphosulfate reductase, Thioredoxin 1 (2 entities in total)
• Functional Keywords: disulfide crosslinked complex, oxidoreductase
• Biological source: Escherichia coli; More
• Cellular location: Cytoplasm: P17854
• Total number of polymer chains: 2
• Total formula weight: 42908.61

Authors

Chartron, J.,Shiau, C.,Stout, C.D.,Carroll, K.S. (deposition date: 2006-12-12, release date: 2007-03-27, Last modification date: 2024-10-30)

Primary citation

Chartron, J.,Shiau, C.,Stout, C.D.,Carroll, K.S.
3'-Phosphoadenosine-5'-phosphosulfate Reductase in Complex with Thioredoxin: A Structural Snapshot in the Catalytic Cycle.
Biochemistry, 46:3942-3951, 2007

PubMed Abstract: 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.

PubMed: 17352498
DOI: 10.1021/bi700130e

Experimental method

X-RAY DIFFRACTION (3 Å)