Addlesee H A, Gibson L C, Jensen P E, Hunter C N
Robert Hill Institute for Photosynthesis, Sheffield, UK.
FEBS Lett. 1996 Jul 1;389(2):126-30. doi: 10.1016/0014-5793(96)00549-2.
A gene from the cyanobacterium Synechocystis sp. PCC 6803 has been cloned and sequenced, and subsequently used to partially complement a bchP mutant of the purple photosynthetic bacterium Rhodobacter sphaeroides. This mutant is blocked in the terminal hydrogenation steps of bchla biosynthesis and possesses only bchl esterified with geranylgeraniol. It also has a reduced cellular level of the light-harvesting LH2 complex, and the 850 nm absorbance maximum of LH2 is red-shifted by approximately 6 nm. Upon heterologous expression of the Synechocystis bchP homologue, not only are hydrogenated forms of bchlaGG detectable, but the level of LH2 is increased and the red-shift reversed by several nm. We conclude that this gene, which we term chlP, encodes the enzyme catalysing the stepwise hydrogenation of geranylgeraniol to phytol during chla biosynthesis.
来自集胞藻属蓝细菌PCC 6803的一个基因已被克隆和测序，随后用于部分互补紫色光合细菌球形红杆菌的bchP突变体。该突变体在叶绿素a生物合成的末端氢化步骤中受阻，仅具有与香叶基香叶醇酯化的叶绿素。它的捕光LH2复合物的细胞水平也降低，并且LH2在850nm处的最大吸光度红移约6nm。在集胞藻bchP同源物的异源表达后，不仅可检测到叶绿素aGG的氢化形式，而且LH2的水平增加，并且红移逆转了几纳米。我们得出结论，这个我们称为chlP的基因编码在叶绿素a生物合成过程中催化香叶基香叶醇逐步氢化为叶绿醇的酶。
