The effect of chemical additives on the bacteriorhodopsin photocycle

✍ Scribed by Zita Batori-Tartsi; Krisztina Ludmann; György Váró

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 569 KB
• Volume: 49
• Category: Article
• ISSN: 1011-1344
• DOI: 10.1016/s1011-1344(99)00058-5

✦ Synopsis

It is demonstrated that gelatin is very effective for preparing dried samples of bacteriorhodopsin because it does not change the spectra and the pbotocycle of the protein, but helps to form a very smooth and stable purple membrane multilayer on the glass surface. In this way, the effect ~f other chemical additives on the photocycle of dried samples of bacteriorhodopsin can be studied. To gain information about the effect ~f triethanolamine on the photocycle, optical absorption kinetic measurements have been carried out on dried samples of bacteriorhodopsiu in a gelatin matrix at different additive concentrations and humidities. Negligible effects are observed on the signals measured in suspe vdon with gelatin and triethanolamine. The photocycle of dried sample slows by two orders of magnitude in the presence of 200-250 molecules of triethanolamine per protein. The effect of water content on the chemically treated dried samples has been studied, giving the longe ;~ lifetime at 0.5 relative humidity. To understand the mechanism of triethanolamine, several bacteriorhodopsin mutants have been investi!.,ated.