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A large geometric distortion in the first photointermediate of rhodopsin, determined by double-quantum solid-state NMR


Abstract Double-quantum magic-angle-spinning NMR experiments were performed on 11,12-13C2-retinylidene-rhodopsin under illumination at low temperature, in order to characterize torsional angle changes at the C11-C12 photoisomerization site. The sample was illuminated in the NMR rotor at low temperature (~120 K) in order to trap the primary photointermediate, bathorhodopsin. The NMR data are consistent with a strong torsional twist of the HCCH moiety at the isomerization site. Although the HCCH torsional twist was determined to be at least 40°, it was not possible to quantify it more closely. The presence of a strong twist is in agreement with previous Raman observations. The energetic implications of this geometric distortion are discussed.

• Content Type Journal Article
• Category Article
• Pages 1-10
• DOI 10.1007/s10858-012-9635-4
• Authors
  • Maria Concistrè, School of Chemistry, University of Southampton, SO17 1BJ Southampton, UK
  • Ole G. Johannessen, School of Chemistry, University of Southampton, SO17 1BJ Southampton, UK
  • Neville McLean, School of Chemistry, University of Southampton, SO17 1BJ Southampton, UK
  • Petra H. M. Bovee-Geurts, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands
  • Richard C. D. Brown, School of Chemistry, University of Southampton, SO17 1BJ Southampton, UK
  • Willem J. DeGrip, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands
  • Malcolm H. Levitt, School of Chemistry, University of Southampton, SO17 1BJ Southampton, UK

• • Journal Journal of Biomolecular NMR
  • Online ISSN 1573-5001
  • Print ISSN 0925-2738

Source: Journal of Biomolecular NMR