3T59

C76A/C455S mutant of mouse QSOX1 containing an interdomain disulfide

Summary for 3T59

• Entry DOI: 10.2210/pdb3t59/pdb
• Related: 3LLI 3LLK 3Q6O 3QCP 3QD9 3T58
• Descriptor: Sulfhydryl oxidase 1, FLAVIN-ADENINE DINUCLEOTIDE (3 entities in total)
• Functional Keywords: oxidoreductase
• Biological source: Mus musculus (mouse)
• Cellular location: Isoform 1: Golgi apparatus membrane; Single- pass membrane protein (By similarity). Isoform 2: Secreted. Isoform 3: Secreted. Isoform 4: Secreted: Q8BND5
• Total number of polymer chains: 4
• Total formula weight: 235549.36

Authors

Fass, D.,Alon, A.,Gat, Y. (deposition date: 2011-07-27, release date: 2012-05-30, Last modification date: 2012-08-29)

Primary citation

Alon, A.,Grossman, I.,Gat, Y.,Kodali, V.K.,DiMaio, F.,Mehlman, T.,Haran, G.,Baker, D.,Thorpe, C.,Fass, D.
The dynamic disulphide relay of quiescin sulphydryl oxidase.
Nature, 488:414-418, 2012

PubMed Abstract: Protein stability, assembly, localization and regulation often depend on the formation of disulphide crosslinks between cysteine side chains. Enzymes known as sulphydryl oxidases catalyse de novo disulphide formation and initiate intra- and intermolecular dithiol/disulphide relays to deliver the disulphides to substrate proteins. Quiescin sulphydryl oxidase (QSOX) is a unique, multi-domain disulphide catalyst that is localized primarily to the Golgi apparatus and secreted fluids and has attracted attention owing to its overproduction in tumours. In addition to its physiological importance, QSOX is a mechanistically intriguing enzyme, encompassing functions typically carried out by a series of proteins in other disulphide-formation pathways. How disulphides are relayed through the multiple redox-active sites of QSOX and whether there is a functional benefit to concatenating these sites on a single polypeptide are open questions. Here we present the first crystal structure of an intact QSOX enzyme, derived from a trypanosome parasite. Notably, sequential sites in the disulphide relay were found more than 40 Å apart in this structure, too far for direct disulphide transfer. To resolve this puzzle, we trapped and crystallized an intermediate in the disulphide hand-off, which showed a 165° domain rotation relative to the original structure, bringing the two active sites within disulphide-bonding distance. The comparable structure of a mammalian QSOX enzyme, also presented here, shows further biochemical features that facilitate disulphide transfer in metazoan orthologues. Finally, we quantified the contribution of concatenation to QSOX activity, providing general lessons for the understanding of multi-domain enzymes and the design of new catalytic relays.

PubMed: 22801504
DOI: 10.1038/nature11267

Experimental method

X-RAY DIFFRACTION (2.8 Å)