7SZE

Structure of the Rieske Non-heme Iron Oxygenase GxtA with Saxitoxin Bound

Summary for 7SZE

• Entry DOI: 10.2210/pdb7sze/pdb
• Descriptor: SxtDIOX, FE2/S2 (INORGANIC) CLUSTER, [(3aS,4R,10aS)-2,6-diamino-10,10-dihydroxy-3a,4,9,10-tetrahydro-3H,8H-pyrrolo[1,2-c]purin-4-yl]methyl carbamate, ... (7 entities in total)
• Functional Keywords: saxitoxin gxta rieske oxygenase metalloprotein iron-sulfur cluster non-heme iron, biosynthetic protein
• Biological source: Microseira wollei
• Total number of polymer chains: 3
• Total formula weight: 117711.77

Authors

Bridwell-Rabb, J.,Liu, J. (deposition date: 2021-11-27, release date: 2022-01-19, Last modification date: 2023-10-18)

Primary citation

Liu, J.,Tian, J.,Perry, C.,Lukowski, A.L.,Doukov, T.I.,Narayan, A.R.H.,Bridwell-Rabb, J.
Design principles for site-selective hydroxylation by a Rieske oxygenase.
Nat Commun, 13:255-255, 2022

PubMed Abstract: Rieske oxygenases exploit the reactivity of iron to perform chemically challenging C-H bond functionalization reactions. Thus far, only a handful of Rieske oxygenases have been structurally characterized and remarkably little information exists regarding how these enzymes use a common architecture and set of metallocenters to facilitate a diverse range of reactions. Herein, we detail how two Rieske oxygenases SxtT and GxtA use different protein regions to influence the site-selectivity of their catalyzed monohydroxylation reactions. We present high resolution crystal structures of SxtT and GxtA with the native β-saxitoxinol and saxitoxin substrates bound in addition to a Xenon-pressurized structure of GxtA that reveals the location of a substrate access tunnel to the active site. Ultimately, this structural information allowed for the identification of six residues distributed between three regions of SxtT that together control the selectivity of the C-H hydroxylation event. Substitution of these residues produces a SxtT variant that is fully adapted to exhibit the non-native site-selectivity and substrate scope of GxtA. Importantly, we also found that these selectivity regions are conserved in other structurally characterized Rieske oxygenases, providing a framework for predictively repurposing and manipulating Rieske oxygenases as biocatalysts.

PubMed: 35017498
DOI: 10.1038/s41467-021-27822-3

Experimental method

X-RAY DIFFRACTION (1.74 Å)