Isolation and Partial Sequence of the A-Protein Gene of Thermus Thermophilus Cytochrome C1 AA3.

摘要

Thermus thermophilus is a strictly aerobic eubacterium which grows optimally near 70C. Its respiratory system is very similar to that of eukaryotic mitochondria, and the organism has proven to be a particularly good source of stable, comparatively simple respiratory enzymes. There are at least two terminal oxidases: The recently discovered cytochrome ba33 and cytochrome c1 aa32 . Cytochrome ba3 is analog of aa3 in which the heme A of cytochrome a is replaced with protoporphyrin IX (heme B) while its order redox components appear to be largely identical to those of the now classical mammalian cytochrome aa3 ; it has only a single 35 kD protein subunit. Cytochrome c1 aa3 consists of two polypeptides. The /approximately/33 kD C-protein covalently binds one heme C, while the /approximately/55 kD protein is thought to bind the four canonical redox centers of aa3 , two heme A, and two Cu. Toward our goal of unequivocally establishing the distribution of the metal centers in cytochrome c1 aa3 , we have isolated the structural gene of the A-protein. 20 refs., 4 figs. (ERA citation 14:001850)