Structural basis for glycyl radical formation by pyruvate formate-lyase activating enzyme.
Pyruvate formate-lyase activating enzyme generates a stable and catalytically essential glycyl radical on G(734) of pyruvate formate-lyase via the direct, stereospecific abstraction of a hydrogen atom from pyruvate formate-lyase. The activase performs this remarkable feat by using an iron-sulfur cluster and S-adenosylmethionine (AdoMet), thus placing it among the AdoMet radical superfamily of enzymes. We report here structures of the substrate-free and substrate-bound forms of pyruvate formate-lyase-activating enzyme, the first structures of an AdoMet radical activase. To obtain the substrate-bound structure, we have used a peptide substrate, the 7-mer RVSGYAV, which contains the sequence surrounding G(734). Our structures provide fundamental insights into the interactions between the activase and the G(734) loop of pyruvate formate-lyase and provide a structural basis for direct and stereospecific H atom abstraction from the buried G(734) of pyruvate formate-lyase.
Departments of Chemistry and Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Jessica L
JL
Vey
Jian
J
Yang
Meng
M
Li
William E
WE
Broderick
Joan B
JB
Broderick
Catherine L
CL
Drennan
D000123:Acetyltransferases; D018360:Crystallography, X-Ray; D004798:Enzymes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D005609:Free Radicals / Q000737:chemistry / Q000378:metabolism; D005998:Glycine / Q000737:chemistry / Q000235:genetics; D008958:Models, Molecular; D011485:Protein Binding; D017510:Protein Folding; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity
D004798:Enzymes; D005609:Free Radicals; D000123:Acetyltransferases; C040285:pyruvate formate-lyase activating enzyme; D005998:Glycine