Solov'ev A A, Makhneva Z K, Erokhin Y U
Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region.
Membr Cell Biol. 2001;14(4):463-74.
We studied UV-induced photodestruction of the native forms of bacteriochlorophyll a (Bchl a) from chromatophores and light harvesting complexes (LHC) of the sulphur photosynthetic bacterium Chromatium minutissimum. Irradiation of chromato- phores with 365-nm light (Soret band) or 280-nm light (absorption region of aromatic amino acids) led to the destruction of all long-wavelength forms of Bchl a. The quantum yields of photodestruction produced by the 280-nm light was higher than that produced by the 365-nm light. For the spectral forms of Bchl a absorbing at 850 nm and 890 nm, the difference was about one order of magnitude, and for the form absorbing at 800 nm the difference was almost two orders of magnitude. Similar UV sensitivity was observed for the Bchl a forms from isolated LHC. As a rule, the quantum yields of photodestruction induced by UV irradiation at 280 nm were about 100-1000 times higher (approximately 10(-3)-10(-4)) than that upon red light irradiation (approximately 10(-6)-10(-7)). We found that irradiation of chromatophores at 280 nm resulted in a crosslink between the core and peripheral LHC.
我们研究了紫外线对极小色硫光合细菌的色素体和光捕获复合体（LHC）中细菌叶绿素a（Bchl a）天然形式的光破坏作用。用365纳米光（索雷特带）或280纳米光（芳香族氨基酸的吸收区域）照射色素体，会导致所有长波长形式的Bchl a被破坏。280纳米光产生的光破坏量子产率高于365纳米光产生的量子产率。对于在850纳米和890纳米处吸收的Bchl a光谱形式，差异约为一个数量级，而对于在800纳米处吸收的形式，差异几乎为两个数量级。从分离的LHC中得到的Bchl a形式也观察到类似的紫外线敏感性。通常，280纳米紫外线照射诱导的光破坏量子产率比红光照射时（约10⁻⁶ - 10⁻⁷）高约100 - 1000倍（约10⁻³ - 10⁻⁴）。我们发现，在280纳米处照射色素体会导致核心LHC和外周LHC之间发生交联。
