The Bacillus subtilis desaturase: a model to understand phospholipid modification and temperature sensing
- First Online:
- Cite this article as:
- Mansilla, M.C. & de Mendoza, D. Arch Microbiol (2005) 183: 229. doi:10.1007/s00203-005-0759-8
- 483 Downloads
Most fatty acid desaturases are members of a large superfamily of integral membrane, O2-dependent, iron-containing enzymes that insert double bonds into previously synthesized fatty acyl chains. The cold shock-induced, membrane-bound desaturase from Bacillus subtilis (Δ5-Des) uses existing phospholipids as substrates to introduce a cis-double bond at the fifth position of the fatty acyl chain. While essentially no three-dimensional structural information is available for these difficult-to-purify enzymes, experimental analysis of the topology of Δ5-Des has provided a model that might be extended to most acyl-lipid desaturases. In addition, studies of the cold-induced expression of Δ5-Des led to the identification of a two-component system composed of a membrane-associated kinase, DesK, and a transcriptional regulator, DesR, which stringently controls the transcription of the des gene, coding for the desaturase. A model for sensing and transduction of low-temperature signals has emerged from our results, which we discuss in the context of transcriptional regulation of membrane lipid fluidity homeostasis.