PDBsum entry 2bjs

Oxidoreductase

PDB id: 2bjs

Contents

Protein chain

320 a.a. *

Ligands

ACV ×2

MEE

SO4

Metals

_FE

Waters ×546

* Residue conservation analysis

PDB id:

2bjs

Name:

Oxidoreductase

Title:

Isopenicillin n synthasE C-terminal truncation mutant

Structure:

Isopenicillin n synthetase. Chain: a. Synonym: ipns, isopenicillin n synthase. Engineered: yes. Mutation: yes

Source:

Emericella nidulans (strain fgsc a4 / atcc 38163 / cbs 112.46 / nrrl 194 / m139). Aspergillus nidulans. Organism_taxid: 227321. Expressed in: escherichia coli. Expression_system_taxid: 562. Other_details: aspergillus nidulans

Resolution:

1.30Å R-factor: 0.140 R-free: 0.164

Authors:

L.A.Mcneill,M.Sami,I.J.Clifton,N.I.Burzlaff

Key ref:

L.A.McNeill et al. (2017). Terminally Truncated Isopenicillin N Synthase Generates a Dithioester Product: Evidence for a Thioaldehyde Intermediate during Catalysis and a New Mode of Reaction for Non-Heme Iron Oxidases. Chemistry, 23, 12815-12824. PubMed id: 28703303

Date:

07-Feb-05 Release date: 09-Mar-06

Protein chain

P05326  (IPNS_EMENI) -  Isopenicillin N synthase from Emericella nidulans (strain FGSC A4 / ATCC 38163 / CBS 112.46 / NRRL 194 / M139)

Seq: 331 a.a.

Struc: 320 a.a.

Enzyme reactions

• Enzyme class: E.C.1.21.3.1 - isopenicillin-N synthase.
• Pathway: Penicillin N and Deacetoxycephalosporin C Biosynthesis
• Reaction: N-[(5S)-5-amino-5-carboxypentanoyl]-L-cysteinyl-D-valine + O2 = isopenicillin N + 2 H2O

N-[(5S)-5-amino-5-carboxypentanoyl]-L-cysteinyl-D-valine + O2 = isopenicillin N + 2 × H2O (Bound ligand (Het Group name = ACV) corresponds exactly)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

Added reference

Chemistry 23:12815-12824 (2017)

PubMed id: 28703303

Terminally Truncated Isopenicillin N Synthase Generates a Dithioester Product: Evidence for a Thioaldehyde Intermediate during Catalysis and a New Mode of Reaction for Non-Heme Iron Oxidases.

L.A.McNeill, T.J.N.Brown, M.Sami, I.J.Clifton, N.I.Burzlaff, T.D.W.Claridge, R.M.Adlington, J.E.Baldwin, P.J.Rutledge, C.J.Schofield.

ABSTRACT

Isopenicillin N synthase (IPNS) catalyses the four-electron oxidation of a tripeptide, l-δ-(α-aminoadipoyl)-l-cysteinyl-d-valine (ACV), to give isopenicillin N (IPN), the first-formed β-lactam in penicillin and cephalosporin biosynthesis. IPNS catalysis is dependent upon an iron(II) cofactor and oxygen as a co-substrate. In the absence of substrate, the carbonyl oxygen of the side-chain amide of the penultimate residue, Gln330, co-ordinates to the active-site metal iron. Substrate binding ablates the interaction between Gln330 and the metal, triggering rearrangement of seven C-terminal residues, which move to take up a conformation that extends the final α-helix and encloses ACV in the active site. Mutagenesis studies are reported, which probe the role of the C-terminal and other aspects of the substrate binding pocket in IPNS. The hydrophobic nature of amino acid side-chains around the ACV binding pocket is important in catalysis. Deletion of seven C-terminal residues exposes the active site and leads to formation of a new type of thiol oxidation product. The isolated product is shown by LC-MS and NMR analyses to be the ene-thiol tautomer of a dithioester, made up from two molecules of ACV linked between the thiol sulfur of one tripeptide and the oxidised cysteinyl β-carbon of the other. A mechanism for its formation is proposed, supported by an X-ray crystal structure, which shows the substrate ACV bound at the active site, its cysteinyl β-carbon exposed to attack by a second molecule of substrate, adjacent. Formation of this product constitutes a new mode of reaction for IPNS and non-heme iron oxidases in general.