Fukui T, Kichise T, Iwata T, Doi Y
Polymer Chemistry Laboratory, RIKEN Institute, Hirosawa 2-1, Wako-shi, Saitama 351-0198, Japan.
Biomacromolecules. 2001 Spring;2(1):148-53. doi: 10.1021/bm0056052.
Analysis of native poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)] inclusions from Aeromonas caviae FA440 revealed that ORF1 (a 348-bp gene located immediately upstream of phaC(Ac)) encodes a 13-kDa granule-associated protein, which was referred to as phaP(Ac). Several recombinant strains of A. caviae were constructed and conducted to analyze their PHA-producing abilities. A transconjugant of FA440 harboring additional copies of phaPCJ(Ac) genes accumulated P(3HB-co-3HHx) copolyesters with much higher 3HHx composition (46-63 mol %) than wild-type strain from alkanoates or olive oil. Deletion analysis revealed that overexpression of phaJ(Ac) encoding monomer-supplying (R)-hydratase was not a reason for the compositional change in the recombinant strains. PHA synthase activity in PHA inclusion fraction from the transconjugant composed of 60 mol % of 3HHx was 10-fold higher than that from the strain FA440 with 13 mol % of 3HHx, suggesting an importance of the level of PHA synthase activity for controlling the PHA composition in vivo.
对豚鼠气单胞菌FA440的天然聚（3-羟基丁酸酯-co-3-羟基己酸酯）[P(3HB-co-3HHx)]内含物的分析表明，ORF1（一个位于phaC(Ac)上游紧邻的348 bp基因）编码一种13 kDa的颗粒相关蛋白，被称为phaP(Ac)。构建了几株豚鼠气单胞菌重组菌株，并对它们的PHA生产能力进行了分析。携带phaPCJ(Ac)基因额外拷贝的FA440转接合子从链烷酸盐或橄榄油中积累的P(3HB-co-3HHx)共聚酯中3HHx的组成比例（46 - 63 mol%）比野生型菌株高得多。缺失分析表明，编码单体供应（R）-水合酶的phaJ(Ac)的过表达不是重组菌株中组成变化的原因。来自3HHx含量为60 mol%的转接合子的PHA内含物部分的PHA合酶活性比3HHx含量为13 mol%的FA440菌株高10倍，这表明PHA合酶活性水平对于体内控制PHA组成具有重要意义。
