PDBsum entry 4xca

Oxidoreductase

PDB id: 4xca

Contents

Protein chains

256 a.a.

242 a.a.

Ligands

AKG ×4

TRS

Metals

_CS ×3

_NI ×4

Waters ×499

PDB id:

4xca

Name:

Oxidoreductase

Title:

Crystal structure of hygx from streptomyces hygroscopicus with nickel and 2-oxoglutarate bound

Structure:

Oxidase/hydroxylase. Chain: a, b, c, d. Engineered: yes

Source:

Streptomyces hygroscopicus subsp. Hygroscopicus. Organism_taxid: 68042. Gene: hygx. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

2.30Å R-factor: 0.181 R-free: 0.236

Authors:

K.M.Mcculloch,E.K.Mccranie,M.Sarwar,J.L.Mathieu,B.L.Gitschlag,Y.Du, B.O.Bachmann,T.M.Iverson

Key ref:

K.M.McCulloch et al. (2015). Oxidative cyclizations in orthosomycin biosynthesis expand the known chemistry of an oxygenase superfamily. Proc Natl Acad Sci U S A, 112, 11547-11552. PubMed id: 26240321 DOI: 10.1073/pnas.1500964112

Date:

17-Dec-14 Release date: 05-Aug-15

Protein chains

Q2MFS1  (Q2MFS1_STRHY) -  Putative oxidase/hydroxylase from Streptomyces hygroscopicus subsp. hygroscopicus

Seq: 258 a.a.

Struc: 256 a.a.

Protein chain

Q2MFS1  (Q2MFS1_STRHY) -  Putative oxidase/hydroxylase from Streptomyces hygroscopicus subsp. hygroscopicus

Seq: 258 a.a.

Struc: 242 a.a.

Enzyme reactions

• Enzyme class: Chains A, B, C, D: E.C.?

DOI no: 10.1073/pnas.1500964112

Proc Natl Acad Sci U S A 112:11547-11552 (2015)

PubMed id: 26240321

Oxidative cyclizations in orthosomycin biosynthesis expand the known chemistry of an oxygenase superfamily.

K.M.McCulloch, E.K.McCranie, J.A.Smith, M.Sarwar, J.L.Mathieu, B.L.Gitschlag, Y.Du, B.O.Bachmann, T.M.Iverson.

ABSTRACT

Orthosomycins are oligosaccharide antibiotics that include avilamycin, everninomicin, and hygromycin B and are hallmarked by a rigidifying interglycosidic spirocyclic ortho-δ-lactone (orthoester) linkage between at least one pair of carbohydrates. A subset of orthosomycins additionally contain a carbohydrate capped by a methylenedioxy bridge. The orthoester linkage is necessary for antibiotic activity but rarely observed in natural products. Orthoester linkage and methylenedioxy bridge biosynthesis require similar oxidative cyclizations adjacent to a sugar ring. We have identified a conserved group of nonheme iron, α-ketoglutarate-dependent oxygenases likely responsible for this chemistry. High-resolution crystal structures of the EvdO1 and EvdO2 oxygenases of everninomicin biosynthesis, the AviO1 oxygenase of avilamycin biosynthesis, and HygX of hygromycin B biosynthesis show how these enzymes accommodate large substrates, a challenge that requires a variation in metal coordination in HygX. Excitingly, the ternary complex of HygX with cosubstrate α-ketoglutarate and putative product hygromycin B identified an orientation of one glycosidic linkage of hygromycin B consistent with metal-catalyzed hydrogen atom abstraction from substrate. These structural results are complemented by gene disruption of the oxygenases evdO1 and evdMO1 from the everninomicin biosynthetic cluster, which demonstrate that functional oxygenase activity is critical for antibiotic production. Our data therefore support a role for these enzymes in the production of key features of the orthosomycin antibiotics.