[NMR paper] Conformational and dynamic differences between N-ras P21 bound to GTPgammaS and to GM

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Conformational and dynamic differences between N-ras P21 bound to GTPgammaS and to GMPPNP as studied by NMR.

Related Articles Conformational and dynamic differences between N-ras P21 bound to GTPgammaS and to GMPPNP as studied by NMR.

Biochemistry. 1997 Apr 22;36(16):5045-52

Authors: Hu JS, Redfield AG

Heteronuclear-edited proton-detected NMR methods are used to study the nucleotide-dependent conformational changes between the GMPPNP form of human N-ras P21 as compared to GDP and GTPgammaS forms. Full-length N-ras P21 was also compared with protein truncated beyond residue 167, to search for interaction points between the more invariant part of the protein and the variable C-terminal section. In both cases, the reporter was the 15N-H 2D spectrum of aspartate amide groups labeled with 15N. Small truncation-induced changes were seen in the spectrum at the resonances of Asp-54, -108, and -109 which are not far from the C-terminal and, surprisingly, at Asp-57 which is more remote. The spectrum obtained for the GMPPNP-ligated form is similar to that of the GTPgammaS form, except that peaks of several residues are weak at low temperature, and strongly temperature-dependent in their intensity, and a new resonance appears at 15 degrees C and above. The observations are discussed in terms of a two-state model for the GMPPNP-ligated protein, previously proposed by Geyer et al. [(1996) Biochemistry 35, 10308-10320].

PMID: 9125526 [PubMed - indexed for MEDLINE]



Source: PubMed