Anti-CHD2 (full length) polyclonal antibody

H-2 spin relaxation NMR experiments to study the dynamics of deuterated backbone alpha-positions, D-alpha, are developed. To date, solution-state H-2 relaxation measurements in proteins have been confined to side-chain deuterons-primarily (CH2D)-C-13 or (CHD2)-C-13 methyl groups. It is shown that quantification of H-2 relaxation rates at D-alpha backbone positions and the derivation of associated order parameters of C-alpha-D-alpha bond vector motions in small [U-N-15, C-13, H-2]-labeled proteins is feasible with reasonable accuracy. The utility of the developed methodology is demonstrated on a pair of proteins-ubiquitin (8.5 kDa) at 10, 27, and 40 degrees C, and a variant of GB1 (6.5 kDa) at 22 degrees C. In both proteins, the D-alpha-derived parameters of the global rotational diffusion tensor are in good agreement with those obtained from N-15 relaxation rates. Semiquantitative solution-state NMR measurements yield an average value of the quadrupolar coupling constant, QCC, for D-alpha sites in proteins equal to 174 kHz. Using a uniform value of QCC for all D-alpha sites, we show that C-alpha-D-alpha bond vectors are motionally distinct from the backbone amide N-H bond vectors, with H-2-derived squared order parameters of C-alpha-D-alpha bond vector motions, S-C alpha D alpha(2), on average slightly higher than their N-H amides counterparts, S-NH(2). For ubiquitin, the H-2-derived backbone mobility compares well with that found in a 1-mu s molecular dynamics simulation.

(2 + 1) resonance-enhanced multiphoton ionization (REMPI) detection of methyl radicals, in particular that via the intermediate 3p Rydberg states, has shown to be a powerful method and thus enjoyed a wide range of applications. Methyl has six vibrational modes. Among them-including partially and fully deuterated isotopologs-four out of twenty vibrational frequencies in the intermediate 3p states have so far eluded direct spectroscopic determination. Here, by exploiting the imaging spectroscopy approach to a few judiciously selected chemical reactions, the four long-sought REMPI bands-CHD2(6(1)(1)), CH2D(3(1)(1)), CH2D(5(1)(1)), and CH2D(6(1)(1))-are discovered, which complete the REMPI identification for probing any vibrational mode of excitation of methyl radical and its isotopologs. These results, in conjunction with those previously reported yet scattered in the literature, are summarized here for ready reference, which should provide all necessary information for further spectral assignments and future studies of chemical dynamics using this versatile REMPI scheme. Published by AIP Publishing.