Blacklock Brenda J, Jaworski Jan G
Department of Chemistry and Chemical Biology, Purdue School of Science, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, 46202, USA.
Biochem Biophys Res Commun. 2006 Jul 28;346(2):583-90. doi: 10.1016/j.bbrc.2006.05.162.
The very long chain fatty acids (VLCFA) incorporated into plant lipids are derived from the iterative addition of C2 units provided by malonyl-CoA to an acyl-CoA by the 3-ketoacyl-CoA synthase (KCS) component of a fatty acid elongase (FAE) complex. Mining of the Arabidopsis genome sequence database revealed 20 genes with homology to seed-specific FAE1 KCS. Eight of the 20 putative KCSs were cloned, expressed in yeast, and isolated as (His)6 fusion proteins. Five of the eight (At1g71160, At1g19440, At1g07720, At5g04530, and At4g34250) had little or no activity with C16 to C20 substrates while three demonstrated activity with C16, C18, and C20 saturated acyl-CoA substrates. At1g01120 KCS (KCS1) and At2g26640 KCS had broad substrate specificities when assayed with saturated and mono-unsaturated C16 to C24 acyl-CoAs while At4g34510 KCS was specific for saturated fatty acyl-CoA substrates.
整合到植物脂质中的超长链脂肪酸（VLCFA）来源于脂肪酸延长酶（FAE）复合体的3-酮酰基辅酶A合酶（KCS）组分将丙二酰辅酶A提供的C2单位迭代添加到酰基辅酶A上。对拟南芥基因组序列数据库的挖掘揭示了20个与种子特异性FAE1 KCS具有同源性的基因。在这20个推定的KCS中，有8个被克隆，在酵母中表达，并作为（His）6融合蛋白分离出来。这8个中的5个（At1g71160、At1g19440、At1g07720、At5g04530和At4g34250）对C16至C20底物几乎没有活性，而3个对C16、C18和C20饱和酰基辅酶A底物表现出活性。当用饱和和单不饱和的C16至C24酰基辅酶A进行测定时，At1g01120 KCS（KCS1）和At2g26640 KCS具有广泛的底物特异性，而At4g34510 KCS对饱和脂肪酰基辅酶A底物具有特异性。
