期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1977
卷号：74
期号：12
页码：5244-5247
DOI：10.1073/pnas.74.12.5244
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Cytochrome c555 is an 86-residue type c cytochrome derived from Chlorobium thiosulfatophilum, an obligately anaerobic green sulfur bacterium which is among the most primitive of living organisms. Here is presented a preliminary structural description of the cytochrome c555 molecule based on its crystallographic structure determination at 2.7-A resolution by multiple isomorphous replacement methods. This structure is of interest not only because of its evolutionary significance but also because the cytochrome c555 molecule possesses an unusually low physiologic oxidoreduction potential (Em,7 = +145 mV) compared with related members of the cytochrome c family. Consequently, determination of its structure may permit a direct assessment of the structural factors responsible for prosthetic group redox potential regulation in type c cytochromes.
