Correction to Structure of a Sedoheptulose 7-Phosphate Cyclase: ValA from Streptomyces hygroscopicus

Shortly after this article describing the crystal structure of ValA from Streptomyces hygroscopicus was accepted for publication, we were able to determine the structure of the related enzyme desmethyl-4-deoxygadusol synthase from Anabaena variabilis (AvDDGS) at a higher (∼1.7 A) resolution (work still in progress). In light of the new structure, we are now able to satisfactorily interpret what we had described as a difficult to fit β-hairpin turn at residues 32 and 33 of ValA that collided with its symmetry mate across the crystallographic 2-fold axis. Rather than these residues forming a β-hairpin to match the chain topology seen in dehydroquionate synthase structures, a domain-swapped arrangement exists in which the residues N-terminal to position 33 continue in a linear direction, making an extended β-strand that participates in the core β-sheet in the other subunit of the dimer. We have updated the Protein Data Bank deposition to reflect this altered topology and provide here an updated version of our original Figure 3 that provides a corrected overview of the topology of ValA. Further details of this new topology will be reported in a future publication of the AvDDGS structure. Figure 3 Overall structure and topology of ValA. (a) Ribbon diagrams of the two chains of the ValA dimer are colored in purple and green tones, with the N-terminal NAD+-binding domains in light hues and the C-terminal metal-binding domains in dark hues. The extended β-strands ...