Zhang Qi, Li Mingchun, Ma Haiting, Sun Ying, Xing Laijun
Department of Microbiology, Nankai University, 300071, Tianjin, PR China.
FEBS Lett. 2004 Jan 2;556(1-3):81-5. doi: 10.1016/s0014-5793(03)01380-2.
A cDNA sequence putatively encoding a Delta(6)-fatty acid desaturase was isolated from Rhizopus arrhizus using reverse transcription polymerase chain reaction and rapid amplification of cDNA ends methods. Sequence analysis indicated that this cDNA sequence had an open reading frame of 1377 bp encoding 458 amino acids of 52 kDa. The deduced amino acid sequence showed high similarity to those of fungal Delta(6)-fatty acid desaturases which comprised the characteristics of membrane-bound desaturases, including three conserved histidine-rich motifs and hydropathy profile. A cytochrome b(5)-like domain was observed at the N-terminus. To elucidate the function of this novel putative desaturase, the coding sequence was expressed heterologously in Saccharomyces cerevisiae strain INVScl. The result demonstrated that the coding product of the sequence exhibited Delta(6)-fatty acid desaturase activity by the accumulation of gamma-linolenic acid.
利用逆转录聚合酶链反应和cDNA末端快速扩增方法，从少根根霉中分离出一个推测编码Δ6-脂肪酸去饱和酶的cDNA序列。序列分析表明，该cDNA序列有一个1377 bp的开放阅读框，编码一个52 kDa的458个氨基酸。推导的氨基酸序列与真菌Δ6-脂肪酸去饱和酶具有高度相似性，这些去饱和酶具有膜结合去饱和酶的特征，包括三个保守的富含组氨酸基序和亲水性图谱。在N端观察到一个细胞色素b5样结构域。为了阐明这种新型推测去饱和酶的功能，将编码序列在酿酒酵母菌株INVScl中进行异源表达。结果表明，该序列的编码产物通过γ-亚麻酸的积累表现出Δ6-脂肪酸去饱和酶活性。
