b6f-Associated Chlorophyll: Structural and Dynamic Contribution to the Different Cytochrome Functions

详细信息    查看全文

• 作者：Agnè ; s de Lacroix de Lavalette ; Giovanni Finazzi ; Francesca Zito
• 刊名：Biochemistry
• 出版年：2008
• 出版时间：May 13, 2008
• 年：2008
• 卷：47
• 期：19
• 页码：5259 - 5265
• 全文大小：3660K
• 年卷期：v.47,no.19(May 13, 2008)
• ISSN：1520-4995

文摘

Cytochromes bc₁/b₆f complexes catalyze electron transfer from lipid- to water-soluble carriers in both the respiratory and photosynthetic processes. They contain several common redox cofactors, while a chlorophyll a molecule, the function of which is still enigmatic, is only present in b₆f-type complexes. In this work, we describe a mutagenesis approach aimed at characterizing the role of this pigment. Mutants of the binding pocket were constructed to obtain cytochrome (cyt) b₆f complexes altered in chlorophyll position and/or stability. On the basis of a combined biochemical and functional analysis, we conclude that the chlorophyll plays a major structural role in the complex. Moreover, the chlorophyll and its binding pocket may also be implicated in the regulation of photosynthetic state transitions, a function that is specific to cyt b₆f complexes.