Heinzelmann Eva, Berger Susanne, Müller Claudia, Härtner Thomas, Poralla Karl, Wohlleben Wolfgang, Schwartz Dirk
Fakultät Biologie, Mikrobiologisches Institut, Mikrobiologie/Biotechnologie, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
Leibniz-Institut für Naturstoff-Forschung und Infektionsbiologie-Hans-Knöll-Institut, Beutenbergstrasse 11, 07745 Jena, Germany.
Microbiology (Reading). 2005 Jun;151(Pt 6):1963-1974. doi: 10.1099/mic.0.27844-0.
The lipopeptide antibiotic friulimicin, produced by Actinoplanes friuliensis, is an effective drug against Gram-positive bacteria, such as methicillin-resistant Staphylococcus epidermidis and Staphylococcus aureus strains. Friulimicin consists of a cyclic peptide core of ten amino acids and an acyl residue linked to an exocyclic amino acid. The acyl residue is essential for antibiotic activity, varies in length from C13 to C15, and carries a characteristic double bond at position Delta cis3. Sequencing of a DNA fragment adjacent to a previously described fragment encoding some of the friulimicin biosynthetic genes revealed several genes whose gene products resemble enzymes of lipid metabolism. One of these genes, lipB, encodes an acyl-CoA dehydrogenase homologue. To elucidate the function of the LipB protein, a lipB insertion mutant was generated and the friulimicin derivative (FR242) produced by the mutant was purified. FR242 had antibiotic activity lower than friulimicin in a bioassay. Gas chromatography showed that the acyl residue of wild-type friulimicin contains a double bond, whereas a saturated bond was present in FR242. These results were confirmed by the heterologous expression of lipB in Streptomyces lividans T7, which led to the production of unsaturated fatty acids not found in the S. lividans T7 parent strain. These results indicate that the acyl-CoA dehydrogenase LipB is involved in the introduction of the unusual Delta cis3 double bond into the acyl residue of friulimicin.
由弗留利游动放线菌产生的脂肽抗生素弗留利霉素，是一种对抗革兰氏阳性菌有效的药物，如耐甲氧西林表皮葡萄球菌和金黄色葡萄球菌菌株。弗留利霉素由一个含十个氨基酸的环肽核心和一个与环外氨基酸相连的酰基残基组成。酰基残基对抗生素活性至关重要，长度从C13到C15不等，并在Δ顺式3位带有一个特征性双键。对与先前描述的编码部分弗留利霉素生物合成基因的片段相邻的一个DNA片段进行测序，揭示了几个基因，其基因产物类似于脂质代谢酶。其中一个基因lipB编码一种酰基辅酶A脱氢酶同源物。为了阐明LipB蛋白的功能，构建了一个lipB插入突变体，并对该突变体产生的弗留利霉素衍生物（FR242）进行了纯化。在生物测定中，FR242的抗生素活性低于弗留利霉素。气相色谱分析表明，野生型弗留利霉素的酰基残基含有一个双键，而FR242中存在一个饱和键。通过在变铅青链霉菌T7中异源表达lipB证实了这些结果，这导致产生了变铅青链霉菌T7亲本菌株中未发现的不饱和脂肪酸。这些结果表明，酰基辅酶A脱氢酶LipB参与了将不寻常的Δ顺式3双键引入弗留利霉素的酰基残基中。
