PDBsum entry 5hv8

Transferase

PDB id: 5hv8

Contents

Protein chain

95 a.a.

Ligands

66S

PDB id:

5hv8

Name:

Transferase

Title:

Solution structure of an octanoyl- loaded acyl carrier protein domain from module mlsa2 of the mycolactone polyketide synthase.

Structure:

Type i modular polyketide synthase. Chain: a. Engineered: yes

Source:

Mycobacterium ulcerans. Organism_taxid: 1809. Gene: mlsa2, mup039c. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008. Expression_system_variant: tuner.

NMR struc:

20 models

Authors:

S.Vance,O.Tkachenko,B.Thomas,M.Bassuni,H.Hong,D.Nietlispach, R.W.Broadhurst

Key ref:

S.Vance et al. (2016). Sticky swinging arm dynamics: studies of an acyl carrier protein domain from the mycolactone polyketide synthase. Biochem J, 473, 1097-1110. PubMed id: 26920023 DOI: 10.1042/BCJ20160041

Date:

28-Jan-16 Release date: 09-Mar-16

Protein chain

Q6MZA5  (Q6MZA5_MYCUA) -  Type I modular polyketide synthase from Mycobacterium ulcerans (strain Agy99)

Seq: 2410 a.a.

Struc: 95 a.a.*

* PDB and UniProt seqs differ at 4 residue positions (black crosses)

DOI no: 10.1042/BCJ20160041

Biochem J 473:1097-1110 (2016)

PubMed id: 26920023

Sticky swinging arm dynamics: studies of an acyl carrier protein domain from the mycolactone polyketide synthase.

S.Vance, O.Tkachenko, B.Thomas, M.Bassuni, H.Hong, D.Nietlispach, W.Broadhurst.

ABSTRACT

Type I modular polyketide synthases (PKSs) produce polyketide natural products by passing a growing acyl substrate chain between a series of enzyme domains housed within a gigantic multifunctional polypeptide assembly. Throughout each round of chain extension and modification reactions, the substrate stays covalently linked to an acyl carrier protein (ACP) domain. In the present study we report on the solution structure and dynamics of an ACP domain excised from MLSA2, module 9 of the PKS system that constructs the macrolactone ring of the toxin mycolactone, cause of the tropical disease Buruli ulcer. After modification ofapoACP with 4'-phosphopantetheine (Ppant) to create theholoform,(15)N nuclear spin relaxation and paramagnetic relaxation enhancement (PRE) experiments suggest that the prosthetic group swings freely. The minimal chemical shift perturbations displayed by Ppant-attached C3and C4acyl chains imply that these substrate-mimics remain exposed to solvent at the end of a flexible Ppant arm. By contrast, hexanoyl and octanoyl chains yield much larger chemical shift perturbations, indicating that they interact with the surface of the domain. The solution structure of octanoyl-ACP shows the Ppant arm bending to allow the acyl chain to nestle into a nonpolar pocket, whereas the prosthetic group itself remains largely solvent exposed. Although the highly reduced octanoyl group is not a natural substrate for the ACP from MLSA2, similar presentation modes would permit partner enzyme domains to recognize an acyl group while it is bound to the surface of its carrier protein, allowing simultaneous interactions with both the substrate and the ACP.