[Effect of a lipopolysaccharide on the conformational state and functional activity of a Yersinia pseudotuberculosis porin].
Changes in the structure and functional activity of porin, a protein from Yersinia pseudotuberculosis, resulting from the removal of lipopolysaccharide (LPS) normally bound with the protein were studied. The treatment of LPS-containing porin with a 30% SDS solution led to an LPS-free protein that, according to the SDS-PAGE, remained to be a trimer. It was shown by CD and UV spectroscopies and intrinsic protein fluorescence that the removal of LPS caused only conformational changes in the porin secondary and tertiary structures. The LPS-free porin folded into a completely beta-structured protein aggregate. The bilayer lipid membrane technique showed that the pore-forming activity of the LPS-free porin decreased, and its concentration should be increased by two orders of magnitude to achieve the same effect. Incubation of the LPS-free porin with LPS led to a porin-LPS complex and affected the character of the protein functional activity. The treatment of the LPS-free porin by octyl glucoside, a nonionic detergent, resulted in the restoration of the protein pore-forming activity. It was suggested that the LPS and detergent provide a definite protein conformation necessary for its functioning.
Novikova
O D
OD
Pacific Institute of Bioorganic Chemistry, Far East Division, Russian Academy of Sciences, Vladivostok, Russia. novikova@piboc.marine.su
Kim
N Iu
NIu
Glazunov
V P
VP
Vakorina
T I
TI
Naberezhnykh
G A
GA
Likhatskaia
G N
GN
Khomenko
V A
VA
Solov'eva
T F
TF
D002850:Chromatography, Gel; D002942:Circular Dichroism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D018272:Porins / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D011487:Protein Conformation; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D015011:Yersinia pseudotuberculosis / Q000737:chemistry*
D008070:Lipopolysaccharides; D018272:Porins