Physiological function of the Pseudomonas putida PpG6 (Pseudomonas oleovorans) alkane hydroxylase: monoterminal oxidation of alkanes and fatty acids
Physiological function of the Pseudomonas putida PpG6 (Pseudomonas oleovorans) alkane hydroxylase: monoterminal oxidation of alkanes and fatty acids
复制标题
恶臭假单胞菌 PpG6（含油假单胞菌）烷烃羟化酶的生理功能：烷烃和脂肪酸的单端氧化
DOI：
10.1128/jb.122.1.93-98.1975
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发表时间：
1975
影响因子：
3.2
通讯作者：
J. Shapiro
中科院分区：
文献类型：
--
作者：
M. Nieder;J. Shapiro
恶臭假单胞菌PPG6能够利用纯化的六到十个碳原子的正构烷烃进行生长。它也可以生长在这些烷烃的初级末端氧化产物和1-十二醇上，但不能生长在相应的2-酮或1，6-己二醇、己二酸或槟榔酸上。可以分离到可逆点突变株，它们同时失去了在所有五种正构烷烃生长底物上生长的能力，但仍然可以在辛醇或正庚醇上生长。具有异柠檬酸裂解酶活性缺陷的醋酸盐阴性突变株不能在偶数烷烃和脂肪酸上生长。对乙酸酯和丙酸或乙酸酯和戊二酸代谢缺陷的双突变株的分析表明，烷烃碳仅被乙酰辅酶A和丙酰辅酶A同化。这些结果支持以下结论：(I)恶臭假单胞菌PPG6的正构烷烃生长专一性是由于全细胞烷烃羟化的底物专一性；(Ii)存在单一的烷烃羟基酶复合体；(Iii)该复合体的生理作用是启动烷烃链的单端氧化；以及(Iv)丁酸到非阳极的直链脂肪酸完全被分子的羧端的β-氧化降解。
Pseudomonas putida PpG6 is able to utilize purified n-alkanes of six to ten carbon atoms for growth. It can also grow on the primary terminal oxidation products of these alkanes and on 1-dodecanol but not on the corresponding 2-ketones or 1,6-hexanediol, adipic acid, or pimelic acid. Revertible point mutants can be isolated which have simultaneously lost the ability to grow on all five n-alkane growth substrates but which can still grow on octanol or nonanol. An acetate-negative mutant defective in isocitrate lysase activity is unable to grow on even-numbered alkanes and fatty acids. Analysis of double mutants defective in acetate and propionate or in acetate and glutarate metabolism shows that alkane carbon is assimilated only via acetyl-coenzyme A and propionyl-coenzyme A. These results support the following conclusions: (i) The n-alkane growth specificity of P. putida PpG6 is due to the substrate specificity of whole-cell alkane hydroxylation; (ii) there is a single alkane hydroxylase enzyme complex; (iii) the physiological role of this complex is to initiate the monoterminal oxidation of alkane chains; and (iv) straight-chain fatty acids from butyric through nonanoic are degraded exclusively by beta-oxidation from the carboxyl end of the molecule.