@article {2274,
	title = {Gd(III) chelates as NMR probes of protein-protein interactions. Case study: rubredoxin and cytochrome c3},
	journal = {Inorg Chem},
	volume = {50},
	number = {21},
	year = {2011},
	note = {<p>1520-510X (Electronic)0020-1669 (Linking)Journal ArticleResearch Support, Non-U.S. Gov{\textquoteright}t</p>
},
	month = {Nov 7},
	pages = {10600-7},
	abstract = {<p>Two cyclen-derived Gd probes, [Gd-DOTAM](3+) and [Gd-DOTP](5-) (DOTAM = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetamide; DOTP = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylenephosphonate)), were assessed as paramagnetic relaxation enhancement (PRE)-inducing probes for characterization of protein-protein interactions. Two proteins, Desulfovibrio gigas rubredoxin and Desulfovibrio gigas cytochrome c(3), were used as model partners. In a (1)H NMR titration it was shown that [Gd-DOTP](5-) binds to cytochrome c(3) near heme IV, causing pronounced PREs, characterized by line width broadenings of the heme methyl resonances at ratios as low as 0.08. A K(d) of 23 +/- 1 muM was calculated based on chemical shift perturbation of selected heme methyl resonances belonging to three different heme groups, caused by allosteric effects upon [Gd-DOTP](5-) binding to cytochrome c(3) at a molar ratio of 2. The other probe, [Gd-DOTAM](3+), caused PREs on a well-defined patch near the metal center of rubredoxin (especially the patch constituted by residues D19-G23 and W37-S45, which broaden beyond detection). This effect was partially reversed for some resonances (C6-Y11, in particular) when cytochrome c(3) was added to this system. Both probes were successful in causing reversible PREs at the partner binding site, thus showing to be good probes to identify partners{\textquoteright} binding sites and since the interaction is reversible to structurally characterize protein complexes by better defining the complex interface.</p>
},
	url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve\&db=PubMed\&dopt=Citation\&list_uids=21957905 },
	author = {Almeida, R. M. and Geraldes, C. F. and Pauleta, S. R. and Moura, J. J.}
}
