Almassy R J, Dickerson R E
Proc Natl Acad Sci U S A. 1978 Jun;75(6):2674-8. doi: 10.1073/pnas.75.6.2674.
The structure of respiratory cytochrome c551 of Pseudomonas aeruginosa, with 82 amino acids, has been solved by x-ray analysis and refined to a crystallographic R factor of 16.2%. It has the same basic folding pattern and hydrophobic heme environment as cytochromes c, c2, and c550, except for a large deletion at the bottom of the heme crevice. This same "cytochrome fold" appears to be present in photosynthetic cytochromes c of green and purple sulfur bacteria, and algal cytochromes f, suggesting a common evolutionary origin for electron transport chains in photosynthesis and respiration.
铜绿假单胞菌呼吸细胞色素c551由82个氨基酸组成，其结构已通过X射线分析解析，并精修至晶体学R因子为16.2%。它与细胞色素c、c2和c550具有相同的基本折叠模式和疏水血红素环境，只是在血红素裂隙底部有一个大的缺失。这种相同的“细胞色素折叠”似乎也存在于绿色和紫色硫细菌的光合细胞色素c以及藻类细胞色素f中，这表明光合作用和呼吸作用中的电子传递链有着共同的进化起源。
