Sastre, Diego E.
Basso, Luis G. M.
Cifuente, Javier O.
[4, 5, 6]
de Mendoza, Diego
Navarro, Marcos V. A. S.
Guerin, Marcelo E.
Total Authors: 9
 Univ Sao Paulo, Inst Fis Sao Carlos, Grp Biofis Mol Sergio Mascarenhas, Sao Carlos, SP - Brazil
 Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Fis, Ribeirao Preto, SP - Brazil
 CIC BioGUNE Technol Pk Bizkaia, Struct Biol Unit, Derio 48160, Vizcaya - Spain
 Ikerbasque, Basque Fdn Sci, Bilbao 48013 - Spain
 Univ Sao Paulo, Inst Quim, Dept Bioquim, Sao Paulo, SP - Brazil
 Inst Biol Mol & Celular Rosario IBR, Rosario, Santa Fe - Argentina
Total Affiliations: 8
Journal of Biological Chemistry;
FEB 14 2020.
Web of Science Citations:
PlsX plays a central role in the coordination of fatty acid and phospholipid biosynthesis in Gram-positive bacteria. PlsX is a peripheral membrane acyltransferase that catalyzes the conversion of acyl-ACP to acyl-phosphate, which is in turn utilized by the polytopic membrane acyltransferase PlsY on the pathway of bacterial phospholipid biosynthesis. We have recently studied the interaction between PlsX and membrane phospholipids in vivo and in vitro, and observed that membrane association is necessary for the efficient transfer of acyl-phosphate to PlsY. However, understanding the molecular basis of such a channeling mechanism remains a major challenge. Here, we disentangle the binding and insertion events of the enzyme to the membrane, and the subsequent catalysis. We show that PlsX membrane binding is a process mostly mediated by phospholipid charge, whereas fatty acid saturation and membrane fluidity remarkably influence the membrane insertion step. Strikingly, the PlsX(L254E) mutant, whose biological functionality was severely compromised in vivo but remains catalytically active in vitro, was able to superficially bind to phospholipid vesicles, nevertheless, it loses the insertion capacity, strongly supporting the importance of membrane insertion in acyl-phosphate delivery. We propose a mechanism in which membrane fluidity governs the insertion of PlsX and thus regulates the biosynthesis of phospholipids in Gram-positive bacteria. This model may be operational in other peripheral membrane proteins with an unprecedented impact in drug discovery/development strategies. (AU)