Role of Ferredoxin and Flavodoxins in Bacillus subtilis

CHAZARRETA-CIFRE, LORENA; MARTIARENA LETICIA CARLA; DIEGO DE MENDOZA; ALTABE, SILVIA (AUTOR CORRESPONDIENTE)

JOURNAL OF BACTERIOLOGY

AMER SOC MICROBIOLOGY

Lugar: Baltimore, Whashington; Año: 2011 vol. 193 p. 4043 - 4048

0021-9193

B. subtilis have a membrane bound desaturase that introduces a cis-double bond at the 5 position of the acyl chains of membrane phospholipids (PLs). This reaction needs electron equivalents and it has been extensively shown that they can be transferred from reduced Fer or cytochrome b5, depending on the type of desaturase. The analysis of the genome of B. subtilis shows three potential candidates that can work as electron donors to the 5-desaturase, Ferredoxin (Fer), and two flavodoxins YkuN and YkuP. We performed mutagenesis of the corresponding genes and tested the ability of these proteins to support B. subtilis desaturase activity ?in vivo?. Disruption of the fer gene or the ykuNOP operon, decreased the unsaturated fatty acids levels. We also analyzed the desaturase activity in a strain that had inactivated the three genes fer, ykuN and ykuP and we found that it does not synthesized unsaturated fatty acids. The present study provides strong evidence for the involvement of ferrredoxin and flavodoxins in the desaturation reaction performed by B. subtilis and even though it has been described that flavodoxins transfer electrons in a variety of redox reactions, this is the first time that they are reported as electron donor for the desaturation reaction in bacteria.