Distance distributions and anisotropy decays of troponin C and its complex with troponin I.

ABSTRACT: We used frequency domain measurements of fluorescence resonance energy transfer to recover the distribution of distances between Met 25 and Cys 98 in rabbit skeletal troponin C. These residues were labeled with dansylaziridine as energy donor and 5-(iodoacetamido)eosin as acceptor and are located on the N- and C-terminal lobes of the two-domain protein, respectively. We developed a procedure to correct for the fraction of the sample that was incompletely labeled with the acceptor independent of chemical data. At pH 7.5 and in the presence of Mg2+, the mean distance was near 15 A with a half-width of the distribution of 15 A; when Mg2+ was replaced by Ca2+, the mean distance increased to 22 A with a decrease in the half-width by 4 A. Similar but less pronounced differences in the mean dista

SUBMITTER: Cheung HC 

PROVIDER: S-EPMC6868476 | biostudies-literature | 1991 May

REPOSITORIES: biostudies-literature