Niedzwiedzki Dariusz M, Orf Gregory S, Tank Marcus, Vogl Kajetan, Bryant Donald A, Blankenship Robert E
Photosynthetic Antenna Research Center, ‡Departments of Biology and Chemistry, Washington University in St. Louis , St. Louis, Missouri 63130, United States.
J Phys Chem B. 2014 Mar 6;118(9):2295-305. doi: 10.1021/jp409495m. Epub 2014 Jan 23.
Bacteriochlorophyll f (BChl f) is a photosynthetic pigment predicted nearly 40 years ago as a fourth potential member of the Chlorobium chlorophyll family (BChl c, d, and e). However, this pigment still has not been found in a naturally occurring organism. BChl c, d, and e are utilized by anoxygenic green photosynthetic bacteria for assembly of chlorosomes--large light-harvesting complexes that allow those organisms to survive in habitats with extremely low light intensities. Recently, using genetic methods on two different strains of Chlorobaculum limnaeum that naturally produce BChl e, two research groups produced mutants that synthesize BChl f and assemble it into chlorosomes. In this study, we present detailed investigations on spectral and dynamic characteristics of singlet excited and triplet states of BChl f with the application of ultrafast time-resolved absorption and fluorescence spectroscopies. The studies were performed on isolated BChl f in various solvents, at different temperatures, and on BChl f-containing chlorosomes in order to uncover any unusual or unfavorable properties that stand behind the lack of appearance of this pigment in natural environments.
细菌叶绿素f（BChl f）是一种光合色素，大约40年前被预测为绿菌属叶绿素家族（BChl c、d和e）的第四个潜在成员。然而，这种色素尚未在天然存在的生物体中被发现。BChl c、d和e被无氧绿色光合细菌用于组装叶绿体——大型光捕获复合体，使这些生物体能够在极低光照强度的栖息地中生存。最近，两个研究小组对两种自然产生BChl e的湖生绿菌菌株采用遗传方法，产生了合成BChl f并将其组装到叶绿体中的突变体。在本研究中，我们应用超快时间分辨吸收光谱和荧光光谱，对BChl f单重激发态和三重态的光谱及动力学特性进行了详细研究。研究在不同溶剂、不同温度下的分离BChl f以及含BChl f的叶绿体上进行，以揭示这种色素在自然环境中未出现背后的任何异常或不利特性。
