AcpM, the meromycolate extension acyl carrier protein of Mycobacterium tuberculosis, is activated by the 4'-phosphopantetheinyl transferase PptT, a potential target of the multistep mycolic acid biosynthesis.

Abstract:

:Modification of acyl carrier proteins (ACP) or domains by the covalent binding of a 4'-phosphopantetheine (4'-PP) moiety is a fundamental condition for activation of fatty acid synthases (FASes) and polyketide synthases (PKSes). Binding of 4'-PP is mediated by 4' phosphopantetheinyl transfersases (PPTases). Mycobacterium tuberculosis (Mtb) possesses two essential PPTases: acyl carrier protein synthase (Mtb AcpS), which activates the multidomain fatty acid synthase I (FAS I), and Mtb PptT, an Sfp-type broad spectrum PPTase that activates PKSes. To date, it has not been determined which of the two Mtb PPTases, AcpS or PptT, activates the meromycolate extension ACP, Mtb AcpM, en route to the production of mycolic acids, the main components of the mycobacterial cell wall. In this study, we tested the enzymatic activation of a highly purified Mtb apo-AcpM to Mtb holo-AcpM by either Mtb PptT or Mtb AcpS. By using SDS-PAGE band shift assay and mass spectrometry analysis, we found that Mtb PptT is the PPTase that activates Mtb AcpM. We measured the catalytic activity of Mtb PptT toward CoA, using an activation assay of a blue pigment synthase, BpsA (a nonribosomal peptide synthase, NRPS). BpsA activation by Mtb PptT was inhibited by Mtb apo-AcpM through competition for CoA, in accord with Mtb AcpM activation. A structural model of the putative interaction between Mtb PptT and Mtb AcpM suggests that both hydrophobic and electrostatic interactions stabilize this complex. To conclude, activation of Mtb AcpM by Mtb PptT reveals a potential target of the multistep mycolic acid biosynthesis.

journal_name

Biochemistry

journal_title

Biochemistry

authors

Zimhony O,Schwarz A,Raitses-Gurevich M,Peleg Y,Dym O,Albeck S,Burstein Y,Shakked Z

doi

10.1021/bi501444e

subject

Has Abstract

pub_date

2015-04-14 00:00:00

pages

2360-71

issue

14

eissn

0006-2960

issn

1520-4995

journal_volume

54

pub_type

杂志文章