Participation of the Surface Structure of Pharaonis Phoborhodopsin, ppR and its A149S and A149V mutants, Consisting of the C-terminal α-helix and E-F Loop, in the Complex-formation with the Cognate Transducer pHtrII, as Revealed by Site-directed 13C Solid

Abstract

Participation of the surface structure of pharaonis phoborhodopsin, ppR and its A149S and A149V mutants, consisting of the C-terminal α-helix and E-F loop, in the complex-formation with the cognate transducer pHtrII, as revealed by site-directed 13 C solid-state NMR and A149V in the complexes with pHtrII: 13 C DD-MAS NMR spectrum of [3-13 C]Ala-A149S complex is rather similar to that of the uncomplexed form, while the corresponding spectral feature of A149V complex is similar to that of ppR complex in the C-terminal tip region. This is because more flexible surface structure detected by the DD-MAS NMR spectra are more directly influenced by the dynamics changes than the CP-MAS NMR. It turned out, therefore, that an altered surface structure of A149S resulted in destabilized complex as viewed from the 13 C NMR spectrum of the surface areas, probably because of modified conformation at the corner of the helix E in addition to the change of hydropathy. It is, therefore, concluded that the surface structure of ppR including the C-terminal α-helix and the E-F loops is directly involved in the stabilization of the complex through conformational stability of the helix E.3

Chemical shift tensor – The heart of NMR: Insights into biological aspects of proteins

“…Site-specific assignments of 13 C NMR signals have been attempted for [1- 13 C]Val-, Pro-, Trp- and, Ile-labeled bR [279–281]. [3- 13 C]Ala-, [1- 13 C]Val-labeled p pR were also utilized for the resonance assignment [282,283]. …”

Phototactic and Chemotactic Signal Transduction by Transmembrane Receptors and Transducers in Microorganisms

“…These results suggest that the structure of SRII is affected by the association with HtrII although these are too small to be detected by X-ray diffraction. From solid-state NMR studies, we reported data representing the structural change of HtrII [51,52], and therefore we conclude that the association affects the conformation of both SRII and HtrII. These conformational changes, however, have only a small effect on the photochemistry [55–57].…”

High‐Resolution Studies of Uniformly 13C,15N‐Labeled RNA by Solid‐State NMR Spectroscopy

“…These studies yield information on internuclear distances, torsion angles, molecular orientation, and functional dynamics. MAS NMR spectroscopy provides a unique opportunity to study macromolecules in their own natural environment, in vitro and in vivo, be it a single purified protein, [1] large multiprotein complexes, [2,3] molecular fibrils, [4] cell organelles, [5] the entire cell or tissue, [6,7] or the whole organism. [8] In addition, solid-state NMR spectroscopy emerges as a powerful tool for the time-resolved study of macromolecular folding and catalysis.…”

“…[23] To improve separation, we derived a new set of coordinates [Eqs. (3) and (4), see also the Supporting Information]. C RFDR MAS NMR spectrum of the 14-mer RNA.…”