Site-selective dynamics of azidolysozyme

The spectroscopic response of and structural dynamics around all azido-modified alanine residues (AlaN3) in lysozyme are characterized. It is found that AlaN3 a positionally sensitive probe for the local dynamics, covering frequency range ?15 cm?1 center line shape. This consistent with findings from selective replacements amino acids PDZ2, which reported span ?10 Val, Ala, or Glu by azidohomoalanine. For fluctuation correlation functions, long-time decay constants ?2 ?1 to ps, compares experimentally measured times 3 ps. Attaching azide can yield decays zero on few ps time scale (i.e., static component ?0 ? 0 ps?1) remaining, contribution ?0.5 ps?1 (corresponding 2.5 cm?1), depending environment 10 scale. magnitude correlates qualitatively degree hydration probe. Although attaching be structurally minimally invasive respect overall protein structure, analysis hydrophobicity indicates modification site differs modified unmodified residues, respectively.