Spectroscopy pterin cofactors

Weak P hyperfine interactions to the desulfo inhibited, formaldehyde inhibited and rapid type I (formamide) Mo(v) species have been detected by CW X-band ENDOR spectroscopy. The hyperfine components could be estimated by performing the experiments at various fields across the entire envelope of 7 = 0 Mo(v) EPR features. The value of the A component was determined to be in the 0.15-0.17 MHz range for all these species while that of the Ax was estimated to be 0.1 MHz. A Mo to P distance of -7-12 A could be estimated from evaluation of the dipolar component of the hyperfine interaction using a simple point dipole approximation. This interaction was attributed to the phosphate group of the pterin cofactor. Similar conclusions were obtained from analysis of the ENDOR spectra given by the low-pH chloride Mo(v) signal of cSO. ... 

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