Dynamic metal coordination controls chemoselectivity in radical halogenases DOI
Elijah N. Kissman, Ioannis Kipouros, Jeffrey W. Slater

et al.

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 20, 2024

Abstract The activation of inert C( sp 3 )-H bonds by non-heme Fe enzymes plays a key role in metabolism, epigenetics, and signaling, while providing powerful biocatalytic platform for the chemical synthesis molecules with increased complexity. In this context, II /α-ketoglutarate-dependent radical halogenases represent broadly interesting system, as they are uniquely capable carrying out transfer diverse array bound anions following C-H activation. Here, we provide first experimental evidence that bifurcation H-atom abstraction rebound is driven both ability dynamic metal coordination sphere to reorganize well second-sphere hydrogen-bond network where only two residues (Asn224 Ile151) necessary sufficient. identification minimal motif provides paradigm understanding evolution catalytic plasticity these yields new insight into design principles which expand their reaction scope.

Language: Английский

Conformational Isomerization of the Fe(III)–OH Species Enables Selective Halogenation in Carrier-Protein-Independent Halogenase BesD and Hydroxylase-Evolved Halogenase DOI
Xin Zhang, Yifan Li, Weishan Yuan

et al.

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(12), P. 9342 - 9353

Published: June 5, 2024

Despite extensive studies, how carrier-protein-independent BesD dictates the reaction toward thermodynamically unfavored halogenation is still elusive. Here, we investigated chlorination versus hydroxylation selectivity in both halogenase and hydroxylase-evolved Chi-14, employing MD simulations QM/MM calculations. In BesD, our calculations have shown that 2OG-assisted O2 activation affords axial Fe(IV)-oxo species responsible for substrate C–H activation. To facilitate following Cl-rebound reaction, nascent Fe(III)–OH has to undergo conformational isomerization equatorial one. This can remove steric effects between radical, thereby enhancing migration of radical Cl− ligand during Cl-rebound. Notably, hydrogen-bond interactions with second-sphere residue Asn are vital maintain unsaturated five-coordination shell Fe center. maintenance essential enabling transition from an orientation. Our results concordance existing experimental findings, underscoring pivotal influence iron coordination dynamics governing catalytic processes nonheme enzymes.

Language: Английский

Citations

6
Coordination dynamics of iron enables the selective C–N coupling but bypasses unwanted C–H hydroxylation in Fe(II)/α-ketoglutarate- dependent non-heme enzymes DOI
Xuan Zhang, Jia Liu,

Langxing Liao

et al.

CHINESE JOURNAL OF CATALYSIS (CHINESE VERSION), Journal Year: 2024, Volume and Issue: 62, P. 131 - 144

Published: July 1, 2024

Language: Английский

Citations

3
An Unusual Ferryl Intermediate and Its Implications for the Mechanism of Oxacyclization by the Loline-Producing Iron(II)- and 2-Oxoglutarate-Dependent Oxygenase, LolO DOI
Juan Pan, Eliott S. Wenger, Chi‐Yun Lin

et al.

Biochemistry, Journal Year: 2024, Volume and Issue: 63(13), P. 1674 - 1683

Published: June 20, 2024

N-Acetylnorloline synthase (LolO) is one of several iron(II)- and 2-oxoglutarate-dependent (Fe/2OG) oxygenases that catalyze sequential reactions different types in the biosynthesis valuable natural products. LolO hydroxylates C2 1-exo-acetamidopyrrolizidine before coupling C2-bonded oxygen to C7 form tricyclic loline core. Each reaction requires cleavage a C–H bond by an oxoiron(IV) (ferryl) intermediate; however, carbons are targeted, carbon radicals have fates. Prior studies indicated substrate-cofactor disposition (SCD) controls site H· abstraction can affect outcome. These indications led us determine whether change SCD from first second might contribute observed reactivity switch. Whereas single ferryl complex hydroxylation was previously shown typical Mössbauer parameters, two complexes accumulate during oxacyclization has highest isomer shift seen date for such abstracts ∼ 20 times faster than does its reported off-pathway C7. The detectable competition with cyclization not enhanced 2H2O solvent, suggesting hydroxyl deprotonated prior C7–H cleavage. observations consistent coordination complex, which may reorient oxo ligand, substrate, or both positions more favorable oxacyclization.

Language: Английский

Citations

2
Tracing the stepwise Darwinian evolution of a plant halogenase DOI
Colin Y. Kim, David W. Kastner, Andrew J. Mitchell

et al.

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 11, 2024

Abstract Halogenation chemistry is rare in plant metabolism, with the chloroalkaloid acutumine produced by Menispermaceae species being only well characterized example, involving a specialized dechloroacutumine halogenase (DAH) from iron(II)- and 2-oxoglutarate-dependent dioxygenase (2ODD) superfamily. While DAH presumed to have evolved an ancestral 2ODD enzyme, broader question of how new enzymes arise through Darwinian processes, such as birth Menispermaceae, remains fundamental challenge understanding metabolic evolution. Here, we investigate DAH’s evolutionary trajectory using chromosomal-level genome assembly Menispermum canadense . By analyzing genomic context M. syntenic regions related plants, show that tandem duplication flavonol synthase ( FLS ) gene, followed series neofunctionalization gene loss events. Through structural modeling, molecular dynamics simulations, site-directed mutagenesis, identify residue changes enabling transition DAH. This functional switch required traversing complex landscape where adaptive peaks were separated deep fitness valleys. Our work illustrates enzymatic functions can lineage-specific pathways gradually reshape active site architecture permissive mutations, ultimately mechanism-switching mutations establish novel catalytic activities.

Language: Английский

Citations

1
Dynamic metal coordination controls chemoselectivity in radical halogenases DOI
Elijah N. Kissman, Ioannis Kipouros, Jeffrey W. Slater

et al.

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 20, 2024

Abstract The activation of inert C( sp 3 )-H bonds by non-heme Fe enzymes plays a key role in metabolism, epigenetics, and signaling, while providing powerful biocatalytic platform for the chemical synthesis molecules with increased complexity. In this context, II /α-ketoglutarate-dependent radical halogenases represent broadly interesting system, as they are uniquely capable carrying out transfer diverse array bound anions following C-H activation. Here, we provide first experimental evidence that bifurcation H-atom abstraction rebound is driven both ability dynamic metal coordination sphere to reorganize well second-sphere hydrogen-bond network where only two residues (Asn224 Ile151) necessary sufficient. identification minimal motif provides paradigm understanding evolution catalytic plasticity these yields new insight into design principles which expand their reaction scope.

Language: Английский

Citations

0