Characterization of ATPase Activity of Free and Immobilized Chromatophore Membrane Vesicles of Rhodobacter sphaeroides

• Published in: Journal of microbiology and biotechnology Vol. 27; no. 12; pp. 2173 - 2179
• Main Authors: Kim, Hyeonjun, Tong, Xiaomeng, Choi, Sungyoung, Lee, Jeong K.
• Format: Journal Article
• Language: English
• Published: Korea (South) 한국미생물·생명공학회 28.12.2017
• Subjects: Adenosine Triphosphatases - metabolism; Anaerobiosis; Ascorbic Acid - pharmacology; Bacterial Chromatophores - enzymology; Biological Transport; Biotinylation; Cold Temperature; Immobilized Proteins - metabolism; Light; Phospholipids - chemistry; Photosynthesis; Rhodobacter sphaeroides - enzymology; Streptavidin - metabolism; 생물학; light-dependent ATPase; immobilization; biotinyl cap phospholipid; Rhodobacter sphaeroides; chromatophore membrane vesicle
• ISSN: 1017-7825; 1738-8872
• DOI: 10.4014/jmb.1708.08068

The intracytoplasmic membrane of readily vesiculates when cells are lysed. The resulting chromatophore membrane vesicle (CMV) contains the photosynthetic machineries to synthesize ATP by ATPase. The light-dependent ATPase activity of CMV was lowered in the presence of O₂, but the activity increased to the level observed under anaerobic condition when the reaction mixture was supplemented with ascorbic acid (≥0.5 mM). Cell lysis in the presence of biotinyl cap phospholipid (bcp) resulted in the incorporation of bcp into the membrane to form biotinylated CMV (bCMV), which binds to streptavidin resin at a ratio of approximately 24 μg bacteriochlorophyll ml resin. The ATPase activity of CMV was not affected by biotinylation, but approximately 30% of the activity was lost by immobilization to resin. Interestingly, the remaining 70% of ATPase activity stayed constant during 7-day storage at 4°C. On the contrary, the ATPase activity of bCMV without immobilization gradually decreased to approximately 40% of the initial level in the same comparison. Thus, the ATPase activity of CMV is sustainable after immobilization, and the immobilized bCMV can be used repeatedly as an ATP generator.