We are currently working on two MAS solid-state NMR methods aimed at determining of three-dimensional molecular structure and demonstrating them in the context of secondary structure determination in peptides. The experiments can be used in complementary fashion to determine the backbone torsion angles ~ and y. The first experiment measures the dipole coupling between two """"""""C carbonyl spin labels, which is a function of the ~ angle, affords the highest sensitivity at 1 20' 1 !~ 0 !~ 1 140' 1. The resolution of the experiment is enhanced by (i) using a y encoded pulse sequence of the C7-type to restore the 13C_13 C homonuclear dipole coupling and (ii) allowing the spin system to evolve under the dipolar interaction for relatively long times (ca. 40ms). In the second experiment, a double quantum state between two carbonyl """"""""C nuclei is simultaneously evolved for a variable time t, under both chemical shielding (CSA) interactions. The evolution profile depends on the relative orientation of the two """"""""C CSA tensors, which is primarily a function of the 0 and V torsion angles. The experiment can be performed at relatively high spinning rates (co/27c - 10 kHz), using with double quantum filtration to suppress the natural abundance """"""""C signals. Numerical simulations indicate good sensitivity and resolution for 0 and xV in many of the biologically interesting regions (experiment has a particularly large dynamic range for torsion angles commonly observed in helical peptides and proteins). Both experiments can be carried out on a peptide specifically 13C labeled at the carbonyl positions of two adjacent'amino acid residues. In our studies, we employed tripeptide L-Ala-L-Gly-L-Gly with labels at Ala- 1 and Gly-2.

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Massachusetts Institute of Technology
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Marintchev, Assen; Edmonds, Katherine A; Marintcheva, Boriana et al. (2009) Topology and regulation of the human eIF4A/4G/4H helicase complex in translation initiation. Cell 136:447-60
Frueh, Dominique P; Arthanari, Haribabu; Koglin, Alexander et al. (2009) A double TROSY hNCAnH experiment for efficient assignment of large and challenging proteins. J Am Chem Soc 131:12880-1
Frueh, Dominique P; Leed, Alison; Arthanari, Haribabu et al. (2009) Time-shared HSQC-NOESY for accurate distance constraints measured at high-field in (15)N-(13)C-ILV methyl labeled proteins. J Biomol NMR 45:311-8
Lentz, Margaret R; Westmoreland, Susan V; Lee, Vallent et al. (2008) Metabolic markers of neuronal injury correlate with SIV CNS disease severity and inoculum in the macaque model of neuroAIDS. Magn Reson Med 59:475-84
Hyberts, Sven G; Heffron, Gregory J; Tarragona, Nestor G et al. (2007) Ultrahigh-resolution (1)H-(13)C HSQC spectra of metabolite mixtures using nonlinear sampling and forward maximum entropy reconstruction. J Am Chem Soc 129:5108-16
Chen, Jingyang; Dupradeau, Francois-Yves; Case, David A et al. (2007) Nuclear magnetic resonance structural studies and molecular modeling of duplex DNA containing normal and 4'-oxidized abasic sites. Biochemistry 46:3096-107
Lentz, Margaret R; Kim, John P; Westmoreland, Susan V et al. (2005) Quantitative neuropathologic correlates of changes in ratio of N-acetylaspartate to creatine in macaque brain. Radiology 235:461-8
Kim, John P; Lentz, Margaret R; Westmoreland, Susan V et al. (2005) Relationships between astrogliosis and 1H MR spectroscopic measures of brain choline/creatine and myo-inositol/creatine in a primate model. AJNR Am J Neuroradiol 26:752-9
Peled, S; Cory, D G; Raymond, S A et al. (1999) Water diffusion, T(2), and compartmentation in frog sciatic nerve. Magn Reson Med 42:911-8
Mo, H; Dai, Y; Pochapsky, S S et al. (1999) 1H, 13C and 15N NMR assignments for a carbon monoxide generating metalloenzyme from Klebsiella pneumoniae. J Biomol NMR 14:287-8

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