Fig. 2.
X-band ENDOR of T. thermophilus GcpE + MEcPP/HMBPP-epoxide reaction intermediate X. (A) 1H Davies ENDOR of GcpE + MEcPP. (B) 1H Davies ENDOR of GcpE + MEcPP, in D2O buffer. (C) 1H Davies ENDOR of GcpE + [u-2H]-MEcPP. (D) 2H Mims ENDOR of GcpE + [u-2H]-MEcPP, difference spectrum (2H-labeled—unlabeled). (E) 1H Davies ENDOR of GcpE + HMBPP epoxide. (F) 13C Mims ENDOR of GcpE + [u-13C]-MEcPP, difference spectrum (13C-labeled—unlabeled). The inset is the unsubtracted ENDOR spectrum of the labeled sample showing the 31P feature. Frequency = 9.66 GHz; spectra were collected at g2 (B0 = 342.2 mT) at 20 K. τ-averaging was used for collecting Mims ENDOR spectra as follows: D , 10 spectra at 8 ns steps with an initial τ = 248 ns; F, 12 spectra at 8 ns steps with an initial τ = 248 ns.