The Bacillus subtilis acyl lipid desaturase is a delta5 desaturase

AGUILAR, P; CABALLERO, G; DE MENDOZA, D; ALTABE, SILVIA (PRIMER AUTOR)

JOURNAL OF BACTERIOLOGY

AMER SOC MICROBIOLOGY

Lugar: Baltimore, Whashington; Año: 2003 vol. 185 p. 3228 - 3231

0021-9193

Fatty acid desaturases are nonheme, iron-containing, oxygen-dependent enzymes involved in regioselective introduction of double bonds in fatty acyl aliphatic chains (12). They are present in all groups of organisms, i.e., bacteria, fungi, plants, and animals, and they play a key role in the maintenance of the proper structure and functioning of biological membranes. Two general classes of fatty acid desaturases have been identified. (i) The acyl carrier protein (ACP) desaturases, which uses acyl-ACPs as substrates, are soluble plant enzymes and plastid-localized ; (ii) the membrane-bound desaturases are found in a wide range of taxa and use acyl-CoA or acyl lipid substrates . They show different consensus motifs . The soluble class contains a consensus motif consisting of carboxylate and histidine ligands that coordinate an active site di-iron cluster, as revealed by the X-ray structure of the castor Ä9 stearoyl-ACP desaturase. The integral membrane class contains a different consensus motif for the putative active site composed of three histidine-rich regions, which are presumably involved in iron binding. Unfortunately, information about substrate specificities, regioselectivities, and structure of membrane desaturases is scarce due to the technical limitations in obtaining large quantities of active forms of such enzymes.