Premium
Membrane‐binding mechanism of a bacterial phospholipid N ‐methyltransferase
Author(s) -
Danne Linna,
Aktas Meriyem,
Gleichenhagen Jan,
Grund Nadine,
Wagner Dominic,
Schwalbe Harald,
Hoffknecht Barbara,
MetzlerNolte Nils,
Narberhaus Franz
Publication year - 2015
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12870
Subject(s) - biology , phospholipid , mechanism (biology) , methyltransferase , membrane , biochemistry , bacteria , microbiology and biotechnology , genetics , gene , methylation , philosophy , epistemology
Summary The membrane lipid phosphatidylcholine ( PC ) is crucial for stress adaptation and virulence of the plant pathogen A grobacterium tumefaciens . The phospholipid N ‐methyltransferase PmtA catalyzes three successive methylations of phosphatidylethanolamine to yield PC . Here, we asked how PmtA is recruited to its site of action, the inner leaflet of the membrane. We found that the enzyme attaches to the membrane via electrostatic interactions with anionic lipids, which do not serve as substrate for PmtA . Increasing PC concentrations trigger membrane dissociation suggesting that membrane binding of PmtA is negatively regulated by its end product PC . Two predicted alpha‐helical regions (α A and α F ) contribute to membrane binding of PmtA . The N ‐terminal helix α A binds anionic lipids in vitro with higher affinity than the central helix α F . The latter undergoes a structural transition from disordered to α‐helical conformation in the presence of anionic lipids. The basic amino acids R 8 and K 12 and the hydrophobic amino acid F 19 are critical for membrane binding by α A as well as for activity of full‐length PmtA . We conclude that a combination of electrostatic and hydrophobic forces is responsible for membrane association of the phospholipid‐modifying enzyme.