BINDING-SITE OF CERULENIN IN FATTY-ACID SYNTHETASE
BINDING-SITE OF CERULENIN IN FATTY-ACID SYNTHETASE
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DOI：
10.1093/oxfordjournals.jbchem.a122739
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发表时间：
1989-05-01
影响因子：
2.7
通讯作者：
IWASAKI, S
中科院分区：
文献类型：
--
作者：
FUNABASHI, H;KAWAGUCHI, A;IWASAKI, S
抗生素 cerulenin (2R, 3S)-2,3-epoxy-4-oxo-7,10-trans,trans-dodecadienamide 可不可逆地抑制酿酒酵母的脂肪酸合成酶。 3 摩尔浅蓝菌素与 1 摩尔酶结合，同时丧失其活性。用碘乙酰胺预处理酶减少了与酶结合的浅蓝素的量。由于已知碘乙酰胺特异性结合缩合反应结构域上的半胱氨酸残基，因此认为浅蓝菌素结合相同的结构域。 [3H]淡蓝素处理的酶的胰蛋白酶消化产生放射性肽；其氨基酸组成为Asx 1、Thr 1、Ser 1、Glx 2、Pro 1、Gly 1、Ala 1、Val 1、Ile 1和Leu 2。该组成包括Kresze等人先前报道的缩合反应位点的所有氨基酸(Thr-Pro-Val-Gly-Ala-Cys)。 (Eur. J. Biochem., 79, 181 [1977])，Cys 除外。当用[3H]淡蓝素处理该酶并依次用胰蛋白酶和羧肽酶P消化时，分离出[3H]淡蓝素-半胱氨酸加合物作为唯一产物。这是通过由未标记的浅蓝菌素和半胱氨酸化学合成的加合物来鉴定的，并通过 1H-、 13C-NMR 和快原子轰击质谱法阐明了其结构。这些结果表明，形成羟基内酰胺环的浅蓝菌素在其环氧碳（C-2位）处与酵母脂肪酸合成酶缩合反应结构域中的半胱氨酸残基的SH基团反应。
An antibiotic cerulenin, (2R, 3S)-2,3-epoxy-4-oxo-7,10-trans,trans-dodecadienamide, irreversibly inhibits fatty acid synthetase from Saccharomyces cerevisiae. Three moles of cerulenin were bound to 1 mol of the enzyme with concomitant loss of its activity. Pretreatment of the enzyme with iodoacetamide reduced the amount of cerulenin bound to the enzyme. Since iodoacetamide is known to specifically bind to the cysteine residue on the condensing reaction domain, cerulenin is considered to bind to the same domain. Tryptic digestion of the [3H]cerulenin-treated enzyme gave a radioactive peptide; its amino acid composition was Asx 1, Thr 1, Ser 1, Glx 2, Pro 1, Gly 1, Ala 1, Val 1, Ile 1, and Leu 2. This composition included all the amino acids of the condensing reaction site (Thr-Pro-Val-Gly-Ala-Cys) previously reported by Kresze et al. (Eur. J. Biochem., 79, 181 [1977]) except for Cys. When the enzyme was treated with [3H]cerulenin and digested successively with trypsin and carboxypeptidase P, a [3H]cerulenin-cysteine adduct was isolated as the sole product. This was identified with the adduct chemically synthesized from non-labeled cerulenin and cysteine, and its structure was elucidated by 1H-, 13C-NMR, and fast atom bombardment mass spectrometry. These results indicate that cerulenin, forming a hydroxy-lactam ring, reacts at its epoxide carbon (C-2 position) with the SH-group of the cysteine residue in the condensing reaction domain of yeast fatty acid synthetase.