title: Experimental evidence of distance-dependent diffusion coefficients of a globular protein observed in polymer aqueous solution forming a network structure on nanometer scale.
abstract: The distance dependence of the diffusion coefficient (DDDC) of a globular protein (cytochrome c) in aqueous hyaluronan (HA) solution, which is a model system for extracellular matrices (ECMs), was measured by a combination of three kinds of spectroscopic measurements of diffusion coefficients, the time and space samplings of which are different. The results of the three methods are plotted against the diffusion distance derived from the consideration of each experimental condition. Due to the characteristic morphology of HA with an effective mesh structure, the proteins showed two extreme diffusion modes: (1) short (<10 nm) diffusion with rare contact with polymer chains; (2) long (>100 nm) diffusion significantly disrupted by polymer chains showing an approximately 30% reduction in diffusion coefficient. The transition from the short diffusion to the long one occurs in a very narrow range (10-100 nm) of diffusion distance and this unique character of HA realizing anomalous diffusion should provide suitable environments for various bioactivities when involved in ECM.
authors.affiliation: RIKEN(The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Masuda
authors.forename: Kiminori
authors.initials: K
authors.lastname: Ushida
authors.forename: Goro
authors.initials: G
authors.lastname: Nishimura
authors.forename: Masataka
authors.initials: M
authors.lastname: Kinjo
authors.forename: Mamoru
authors.initials: M
authors.lastname: Tamura
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Koshino
authors.forename: Koichi
authors.initials: K
authors.lastname: Yamashita
authors.forename: Thomas
authors.initials: T
authors.lastname: Kluge