RT Journal Article
SR Electronic
T1 Novel heme-binding enables allosteric modulation in an ancient TIM-barrel glycosidase
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.05.27.118968
DO 10.1101/2020.05.27.118968
A1 Gamiz-Arco, Gloria
A1 Gutierrez-Rus, Luis I.
A1 Risso, Valeria A.
A1 Ibarra-Molero, Beatriz
A1 Hoshino, Yosuke
A1 Petrović, Dušan
A1 Romero-Rivera, Adrian
A1 Seelig, Burckhard
A1 Gavira, Jose A.
A1 Kamerlin, Shina C.L.
A1 Gaucher, Eric A.
A1 Sanchez-Ruiz, Jose M.
YR 2020
UL http://biorxiv.org/content/early/2020/05/28/2020.05.27.118968.abstract
AB Glycosidases are phylogenetically widely distributed enzymes that are crucial for the cleavage of glycosidic bonds. Here, we present the exceptional properties of a putative ancestor of bacterial and eukaryotic family-1 glycosidases. The ancestral protein shares the TIM-barrel fold with its modern descendants but displays large regions with greatly enhanced conformational flexibility. Yet, the barrel core remains comparatively rigid and the ancestral glycosidase activity is stable, with an optimum temperature within the experimental range for thermophilic family-1 glycosidases. None of the ~5500 reported crystallographic structures of ~1400 modern glycosidases show a bound porphyrin. Remarkably, the ancestral glycosidase binds heme tightly and stoichiometrically at a well-defined buried site. Heme binding rigidifies this TIM-barrel and allosterically enhances catalysis. Our work demonstrates the capability of ancestral protein reconstructions to reveal valuable but unexpected biomolecular features when sampling distant sequence space. The potential of the ancestral glycosidase as a scaffold for custom catalysis and biosensor engineering is discussed.Competing Interest StatementThe authors have declared no competing interest.