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Dynamic light scattering study of suspensions of purple membrane

1985; Elsevier BV; Volume: 23; Issue: 1-2 Linguagem: Inglês

10.1016/0301-4622(85)80060-0

1873-4200

Kenji Kubota, Yasunori Tominaga, Satoru Fujime, Jun Otomo, Akira Ikegami,

Light effects on plants

Purple membrane from Halobacterium halobium in suspensions has been studied by quasielastic light scattering. The intensity correlation functions of polarized scattered light were measured at various K2 values (K being the magnitude of the scattering vector), and the first cumulant Γ of the field correlation function G1 (τ) was obtained by a cumulant expansion method. The apparent diffusion coefficient Γ/K2 did not increase monotonically with K2 values and showed a distinct anomaly in an intermediate range of K. A theoretical formulation of G1(τ) for a disc and an extremely oblate ellipsoidal shell of revolution (S. Fujime and K. Kubota, Biophys. Chem. 23 (1985) 1) was applied to the analysis of the spectra, and characteristic features of experimental spectra were well reproduced. It was suggested that a strong interference effect between scattered rays on Γ/K2 should be attributed to a slight noncircular shape of the purple membrane and that a contribution to Γ/K2 from membrane flexibility should be taken into account. This study will provide experimental evidence of the feasibility of membrane studies by dynamic light scattering.