PDBsum entry 4lz3

Lyase

PDB id: 4lz3

Contents

Protein chain

340 a.a.

Ligands

GOL ×4

POP

BTM

_PI

Metals

_MG ×3

Waters ×268

PDB id:

4lz3

Name:

Lyase

Title:

F95h epi-isozizaene synthase: complex with mg, inorganic pyrophosphate and benzyl triethyl ammonium cation

Structure:

Epi-isozizaene synthase. Chain: a. Synonym: eizs, sesquiterpene cyclase, sesquiterpene synthase. Engineered: yes. Mutation: yes

Source:

Streptomyces coelicolor. Organism_taxid: 100226. Strain: a3(2). Gene: cyc1, sco5222, sc7e4.19. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

2.10Å R-factor: 0.164 R-free: 0.204

Authors:

R.Li,W.Chou,J.A.Himmelberger,K.Litwin,G.Harris,D.E.Cane, D.W.Christianson

Key ref:

R.Li et al. (2014). Reprogramming the chemodiversity of terpenoid cyclization by remolding the active site contour of epi-isozizaene synthase. Biochemistry, 53, 1155-1168. PubMed id: 24517311 DOI: 10.1021/bi401643u

Date:

31-Jul-13 Release date: 18-Dec-13

Protein chain

Q9K499  (CYC1_STRCO) -  Epi-isozizaene synthase from Streptomyces coelicolor (strain ATCC BAA-471 / A3(2) / M145)

Seq: 361 a.a.

Struc: 341 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.4.2.3.37 - epi-isozizaene synthase.
• Reaction: (2E,6E)-farnesyl diphosphate = ⁺-epi-isozizaene + diphosphate

(2E,6E)-farnesyl diphosphate = (+)-epi-isozizaene + diphosphate (Bound ligand (Het Group name = POP) corresponds exactly)

• Cofactor: Mg(2+)

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

reference

DOI no: 10.1021/bi401643u

Biochemistry 53:1155-1168 (2014)

PubMed id: 24517311

Reprogramming the chemodiversity of terpenoid cyclization by remolding the active site contour of epi-isozizaene synthase.

R.Li, W.K.Chou, J.A.Himmelberger, K.M.Litwin, G.G.Harris, D.E.Cane, D.W.Christianson.

ABSTRACT

The class I terpenoid cyclase epi-isozizaene synthase (EIZS) utilizes the universal achiral isoprenoid substrate, farnesyl diphosphate, to generate epi-isozizaene as the predominant sesquiterpene cyclization product and at least five minor sesquiterpene products, making EIZS an ideal platform for the exploration of fidelity and promiscuity in a terpenoid cyclization reaction. The hydrophobic active site contour of EIZS serves as a template that enforces a single substrate conformation, and chaperones subsequently formed carbocation intermediates through a well-defined mechanistic sequence. Here, we have used the crystal structure of EIZS as a guide to systematically remold the hydrophobic active site contour in a library of 26 site-specific mutants. Remolded cyclization templates reprogram the reaction cascade not only by reproportioning products generated by the wild-type enzyme but also by generating completely new products of diverse structure. Specifically, we have tripled the overall number of characterized products generated by EIZS. Moreover, we have converted EIZS into six different sesquiterpene synthases: F96A EIZS is an (E)-β-farnesene synthase, F96W EIZS is a zizaene synthase, F95H EIZS is a β-curcumene synthase, F95M EIZS is a β-acoradiene synthase, F198L EIZS is a β-cedrene synthase, and F96V EIZS and W203F EIZS are (Z)-γ-bisabolene synthases. Active site aromatic residues appear to be hot spots for reprogramming the cyclization cascade by manipulating the stability and conformation of critical carbocation intermediates. A majority of mutant enzymes exhibit only relatively modest 2-100-fold losses of catalytic activity, suggesting that residues responsible for triggering substrate ionization readily tolerate mutations deeper in the active site cavity.