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Purification and characterization of ribosomal proteins from the 30 S subunit of the extreme halophile Halobacterium marismortui
Author(s) -
Shoham M.,
Dijḱ J.,
Reinhardt R.,
Wittmann-Liebold B.
Publication year - 1986
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(86)80837-7
Subject(s) - halobacterium , ribosomal protein , halophile , circular dichroism , protein subunit , chemistry , protein secondary structure , size exclusion chromatography , denaturation (fissile materials) , crystallography , halobacteriaceae , electrophoresis , biochemistry , halobacterium salinarum , biology , ribosome , archaea , bacteria , rna , enzyme , nuclear chemistry , gene , genetics
Ribosomal proteins were extracted from 30 S subunits of Halobacterium marismortui under native conditions. Their separation was based on gel filtration and hydrophobic chromatography, performed at a concentration of 3.2 M KCl to avoid denaturation. A total of nine proteins were isolated, purified and identified by partial amino‐terminal sequences and two‐dimensional gel electrophoresis. There is a high degree of sequence homology with 30 S proteins from H. cutirubrum , and also some with 30 S proteins of eubacteria. Proton NMR data indicate unfolding of the proteins in low salt. One of the proteins, however, retains its secondary structure at a salt concentration as low as 0.1 M NaCl, and even in 8 M urea. One reason for this outstanding stability could be the high proportion (50%) of β‐structure in this protein as determined from circular dichroism measurements. In general, there is a higher β‐sheet content than for 30 S proteins from Escherichia coli . Measurements of Stokes radii indicate several of the proteins to have a rather elongated shape. One of these is a complex consisting of L3/L4 and L20, similar to the L8‐complex from E. coli. The presence of this 50 S complex in the preparation of the small subunit suggests a location on the interface between the subunits.