Morelle N, Simorre J P, Caffrey M, Meyer T, Cusanovich M, Marion D
Laboratoire de Résonance Magnétique Nucléaire, Institut de Biologie Structurale Jean-Pierre Ebel (CEA-CNRS), Grenoble, France.
FEBS Lett. 1995 May 29;365(2-3):172-8. doi: 10.1016/0014-5793(95)00450-n.
The 1H resonances of the ferrocytochrome c555 from the anaerobic green sulfur bacterium Chlorobium limicola f thio-sulfatophilum (strain Tassajara) have been assigned. Identification of spin systems and sequential assignment of 1H was accomplished by automated assignment computer programs followed by manual verification. In addition, 13C resonances have been extensively assigned by HSQC experiments at natural abundance. As determined by short-range NOE connectivities, 13C alpha chemical shifts, and HN exchange experiments, the secondary structure consists of 3 helices ranging from residues 3-13, 43-53 and 70-86. Interestingly, the second helix is significantly longer than observed by X-ray crystallography [1977, Proc. Natl. Acad. Sci. USA 74, 5244-5247]. A topological model of the cytochrome c555 is presented based on a small number of long-range NOE contacts. The helices are shown to pack onto the heme according to the pattern common to all class I cytochromes c.
