Structure and Function of Pore-Forming Proteins from Bacteria of the Genus Yersinia: I. Isolation and a Comparison of Physicochemical Properties and Functional Activity of Yersinia Porins

O. P. Vostrikova,^# N. Yu. Kim, G. N. Likhatskaya, K. V. Guzev, T. I. Vakorina, V. A. Khomenko, O. D. Novikova, and T. F. Solov'eva

^# Phone: (4232) 31-0719; fax: (4232) 31-4050; e-mail: o_vl@piboc.dvo.ru Pacific Institute of Bioorganic Chemistry, Far East Division, Russian Academy of Sciences, pr. 100-letiya Vladivostoka 159, Vladivostok, 690022 Russia
Received August 11, 2005; in final form, October 10, 2005

Abstract: The molecular organization and functional activity of porins isolated from the outer membrane (OM) of the Yersinia enterocolitica and three phylogenetically close nonpathogenic Yersinia species (Y. intermedia, Y. kristensenii, and Y. frederiksenii) cultured at 6--8ºC were comparatively studied for the first time. The proteins were isolated in two molecular forms (trimeric and monomeric), and their spatial structures were characterized by the methods of optical spectroscopy, CD and intrinsic protein fluorescence. The studied porins were shown to belong to the β-structural proteins (they have 59--96% total β structures and 0--17% α helices). The spatial structures of the proteins were demonstrated to depend on the nature of the detergent used for solubilization. Unlike the enterobacterial pore-forming proteins, the porin trimers are less stable to sodium dodecyl sulfate (SDS). The spatial structures of the porins become more compact after the substitution of octyl β-D-glucoside for SDS: the content of β structures increases and the accessibility of Trp residues to solvent decreases. It was established with the use of the technique of bilayer lipid membranes that the functional properties of the porins are similar to those of the OmpF proteins of Gram-negative bacteria. Trimers are functionally active forms of the porins. Special features of the pore-forming activity of the Yersinia porins were revealed to depend on the microorganism species and the value of the membrane potential.

Key words: Yersinia genus bacteria, porins of outer membrane, spatial structure, functional activity

Russian Journal of Bioorganic Chemistry 2006, 32 (4):333-344