H. Sagami et al., A NOVEL TYPE OF PROTEIN MODIFICATION BY ISOPRENOID-DERIVED MATERIALS - DIPHYTANYLGLYCERYLATED PROTEINS IN HALOBACTERIA, The Journal of biological chemistry, 270(25), 1995, pp. 14851-14854
Previous work from this laboratory has shown that a derivative of [H-3
]mevalonic acid is incorporated into a number of specific proteins in
Halobacterium halobium and Halobacterium cutirubrum and that the major
radioactive material released by treatment with methyl iodide was nei
ther farnesyl nor geranylgeranyl compound, which have been generally a
ccepted to be prenyl groups of a number of prenylated proteins found i
n eukaryotic cells, but an unknown compound (Sagami, H., Kikuchi, A.,
and Ogura, K. (1994) Biochem. Biophys. Res. Commun, 203, 972-978). In
the current study, the unknown compound was prepared in a large amount
from H. halobium cells and analyzed by reverse and normal phase high
performance liquid chromatographies followed by mass spectrometry. The
mass spectrum of this compound exhibited a parent ion peak (M(+)) at
m/z 682, suggesting that it is a -di-O-(3',7',11',15'-tetramethylhexad
ecyl)glycerol (diphytanylglyceryl methylthioether). Diphytanylglyceryl
methyl thioether was chemically synthesized, and its mass fragmentati
on pattern was completely coincident with that of the mevalonic acid-d
erived material from H. halobium. These results indicate that Halobact
eria contains specific proteins with a novel type of modification of a
cysteine residue of the proteins with a diphytanylglyceryl group in t
hioether linkage.