Anglysis of novel gevefor proline analogue resistance found in budding yesst Σ12786

我们最近发现，在芽殖酵母酿酒酵母1278 b的染色体上，一个新的基因MPR 1（西格玛1278 b基因L-脯氨酸类似物抗性）所需的1278背景菌株毒性AZC的抗性。MPR 1和MPR 2基因均在85位有一个氨基酸的改变，分别存在于背景菌株的XIV和X染色体上，但在S.酿酒酵母S288 C用于基因组序列测定.大肠杆菌中的基因表达和酶分析表明，MPR 1编码一种新型AZC乙酰转移酶，L-脯氨酸本身和其他L-脯氨酸类似物不被乙酰化。MPR 1编码的蛋白质（Mprlp）被认为是N-乙酰转移酶超家族的成员。我们认为AZC在细胞质中被Mprlp转化为N-乙酰AZC，因此在蛋白质的生物合成过程中，N-乙酰AZC不再取代L-脯氨酸.通过对S.酿酒酵母复合种、S.而异歧瓢虫对AZC具有抗性和乙酰转移酶活性。从S.根据MPR 1基因序列设计引物，通过PCR方法分离到一株奇异变形杆菌。基因表达和酶促分析表明，克隆的Spa MPR 1编码AZC乙酰转移酶，其与Mprlp.4具有87%的同一性。预测的Mprlp的氨基酸序列是同源的裂殖酵母粟酒裂殖酵母假设的23.8 kDa的蛋白质。我们分析了S。ppr1^+（pombe MPR1）。该基因与S. pombe编码一种乙酰转移酶，该酶能以类似于MPR 1的方式对AZC进行解毒。我们的研究结果表明，该酶除了对不常见的亚氨基酸AZC进行解毒外，还具有生理上保守的功能。

We recently have discovered, on the chromosome of the budding yeast Saccharmyces cerevisiae Σ1278b, a novel gene MPR1 (sigma 1278b gene for L-proline-analogue resistance) required for the resistance of Σ1278 backgraound strains to toxic AZC.1. The genes MPR1 and MPR2, both characterized by one amino acid change at position 85, were present on chromosomes XIV and X of Σ1278b background strains, respectively, but were absent in the S. cerevisiae S288C used for the genomic sequence determination.2. Gene expression in Escherichia coli and enzymatic analysis showed that MPR1 encodes a novel AZC acetyltransferase, by which L-proline itself and other L-proline analogues are not acetylated. The MPR1-encoded protein (Mprlp) was considered to be a member of the N-acetyltansferase superfamily. We believe that AZC is converted to N-acetyl AZC by Mprlp in the cytoplasm, and consequently, N-acetyl AZC no longer replaces L-proline during the biosynthesis of protein.3. By the comparative analysis of MPR1 in the S. cerevisiae complex species, the type strain of S. paradoxus exhibited resistance and acetyltransferase activity to AZC. The new MPR1 homologue (Spa MPR1) from S. paradoxus was isolated by PCR with the primers based on the sequence of MPR1. Gene expression and enzymatic analysis showed that the cloned Spa MPR1 encodes an AZC acetyltransferase, which has 87% identity to Mprlp.4. The amino acid sequence of the predicted Mprlp was homologous to that of the fission yeast Schizosaccharomyces pombe hypothetical 23.8 kDa protein. We analyzed the S. pombe homologue of MPR1, ppr1^+ (pombe MPR1). This gene was responsibel to the AZC resistance of S. pombe and encodes an acetyltransferase that detoxifies AZC in a manner similar to that by MPR1.Our findings here suggest that this enzyme may have a physiologically conserved function additional to that of detoxifying unusual imino acid AZC.