STUDY OF DYNAMICS OF HUMAN SERUM-ALBUMIN BY COHERENT RAYLEIGH-SCATTERING OF MOSSBAUER RADIATION

The angle dependences Of total and elastic intensities of Rayleigh sca ttering of Mossbauer radiation were measured for human serum albumin ( HSA) with two degrees of hydration: h = 0.13 and 0.4. An extended mode l was developed for calculating the inelastic intensity of Rayleigh sc attering. Original data for HSA and published data for myoglobin (Met- Mb) were fitted within the framework of this model. The best agreement with experiment was obtained when account was taken of two types of i ntraglobular motions: individual motions of small side-chain groups, a nd cooperative (mechanical) motions of segments (most probably alpha-h elices). Long-range correlated motions are essential at low degree of hydration. The possibilities of applying the coherent version of the R SMR technique are described.