Determination of the solution conformation of dephospho coenzyme A by nuclear-magnetic-resonance spectroscopy with lanthanide probes. A method for analysis when more than one complex species is present.
The aqueous solution conformation of the 1 : 1 complex of dephospho CoA bound to a lanthanide ion has been determined by examination of the dipolar shift and induced relaxation at pH 6.4. The experimental data are shown to arise from the presence of both 1 : 1 and 1 : 2 metal : ligand complexes and a graphical method is described to divide the experimental data into information corresponding to each of the two species. The formation constants are also derived. For the 1 : 1 complex the ribose is found in a 2E conformation with the adenine base predominantly anti. A small contribution from a syn conformation is evident. The pantoinic acid fragment of the chain is folded back towards the pyrophosphate while the remainder of the chain is extended.
D000241:Adenosine; D003065:Coenzyme A / Q000031:analogs & derivatives*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008433:Mathematics; D008674:Metals, Rare Earth; D008958:Models, Molecular; D008968:Molecular Conformation; D010204:Pantetheine; D011221:Praseodymium
D008674:Metals, Rare Earth; C015787:dephosphocoenzyme A; D010204:Pantetheine; D000241:Adenosine; D011221:Praseodymium; D003065:Coenzyme A