Wei Dongsheng, Li Mingchun, Zhang Xinxin, Ren Yong, Xing Laijun
Department of Microbiology, Nankai University, Tianjin 300071, PR China.
FEBS Lett. 2004 Aug 27;573(1-3):45-50. doi: 10.1016/j.febslet.2004.06.100.
Based on the sequence information of Delta12-fatty acid desaturase genes (from Mucor circinelloides, Mortierella alpina, Mucor rouxii and Aspergillus nidulans), which were involved in the conversion from C18:1 to C18:2, a cDNA sequence putatively encoding a Delta12-fatty acid desaturase was isolated from Rhizopus arrhizus using the combination of reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) methods. Sequence analysis indicated that it had an open reading frame (ORF) of 1170 bp, coding for 389 amino acid residues of 45 kDa, pI of the deduced protein was 7.01. The deduced amino acid sequence of this cloned cDNA showed high identity to those filamentous fungal Delta12-desaturases mentioned above, including three conserved histidine-rich motifs and two hydrophobic domains. Functional identification was done heterologously in Saccharomyces cerevisiae strain INVScl. The result demonstrated that the deduced amino acid sequence exhibited Delta12-fatty acid desaturase activity, suggesting that this gene encoded for a membrane-bound desaturase, Delta12-fatty acid desaturase.
基于参与从C18:1向C18:2转化的Δ12-脂肪酸去饱和酶基因（来自卷枝毛霉、高山被孢霉、鲁氏毛霉和构巢曲霉）的序列信息，通过逆转录-聚合酶链反应（RT-PCR）和cDNA末端快速扩增（RACE）方法相结合，从少根根霉中分离出一个推测编码Δ12-脂肪酸去饱和酶的cDNA序列。序列分析表明，它有一个1170 bp的开放阅读框（ORF），编码一个45 kDa的389个氨基酸残基，推导蛋白的pI为7.01。该克隆cDNA推导的氨基酸序列与上述丝状真菌的Δ12-去饱和酶具有高度同源性，包括三个保守的富含组氨酸基序和两个疏水结构域。在酿酒酵母菌株INVScl中进行了异源功能鉴定。结果表明，推导的氨基酸序列表现出Δ12-脂肪酸去饱和酶活性，表明该基因编码一种膜结合去饱和酶，即Δ12-脂肪酸去饱和酶。
