Cloning and Characterization of the Zymobacter palmae Pyruvate Decarboxylase Gene (pdc) and Comparison to Bacterial Homologues
Cloning and Characterization of the Zymobacter palmae Pyruvate Decarboxylase Gene (pdc) and Comparison to Bacterial Homologues
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DOI：
10.1128/aem.68.6.2869-2876.2002
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发表时间：
2002-06
影响因子：
4.4
通讯作者：
K. C. Raj;Lee A. Talarico;L. Ingram;J. Maupin-Furlow
中科院分区：
文献类型：
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作者：
K. C. Raj;Lee A. Talarico;L. Ingram;J. Maupin-Furlow
丙酮酸脱羧酶（PDC）是全乙醇发酵过程中的关键酶。虽然PDC广泛分布于植物、酵母和真菌中，但在动物中不存在，在细菌中也很少见（仅在三种生物中发现）。编码三种已知细菌pdc基因的基因先前已被描述并表达为活性重组蛋白。来自活动单胞菌的pdc基因已被用于设计用于工业的乙醇生产生物催化剂。本文描述了一种新的棕榈酵母菌pdc基因。该基因的密码子使用模式似乎与大肠杆菌基因非常相似。在大肠杆菌重组体中，棕榈Z. PDC约占可溶性蛋白的1/3。将Z. palmae酶的生化和动力学性质与其他三种细菌纯化的PDCs进行了比较。在4种细菌的PDCs中，Z. palmae酶的比活性最高（130 U mg蛋白−1），对丙酮酸的比活性最低（0.24 mM）。生物化学性质、热稳定性和密码子使用的差异可能为开发用于燃料乙醇生产的新型生物催化剂提供独特的优势。
ABSTRACT Pyruvate decarboxylase (PDC) is the key enzyme in all homo-ethanol fermentations. Although widely distributed among plants, yeasts, and fungi, PDC is absent in animals and rare in bacteria (established for only three organisms). Genes encoding the three known bacterial pdc genes have been previously described and expressed as active recombinant proteins. The pdc gene from Zymomonas mobilis has been used to engineer ethanol-producing biocatalysts for use in industry. In this paper, we describe a new bacterial pdc gene from Zymobacter palmae. The pattern of codon usage for this gene appears quite similar to that for Escherichia coli genes. In E. coli recombinants, the Z. palmae PDC represented approximately 1/3 of the soluble protein. Biochemical and kinetic properties of the Z. palmae enzyme were compared to purified PDCs from three other bacteria. Of the four bacterial PDCs, the Z. palmae enzyme exhibited the highest specific activity (130 U mg of protein−1) and the lowest Km for pyruvate (0.24 mM). Differences in biochemical properties, thermal stability, and codon usage may offer unique advantages for the development of new biocatalysts for fuel ethanol production.