Biochemical fractionation of starved M. xanthus cells.
(A) Wild-type cells (DK1622) were starved for 24 h on TPM-agar. The
total cell lysate (T) was separated into fractions enriched for soluble
proteins (S), inner membrane proteins (I), and outer membrane proteins (O).
The fractions were subjected to immunoblot analyses and probed with anti-p25
antibodies. As controls, the association of FruA, FrzCD, and AglU with the
different fractions was determined using anti-FruA, anti-FrzCD, and anti-AglU
antibodies, respectively. (B) pilA cells (DK10407), which
are unable to synthesize type IV pili; dsp cells (DK3470), which are
unable to synthesize extracellular fibrils; and wzm cells (HK1321),
which are deficient in lipopolysaccharide O-antigen synthesis, were starved
and fractionated as in A and probed with anti-p25 antibodies.
(C) DK1622/pTK98-10 cells were starved for 24 h. The lysate was phase
separated with Triton X-114 into an aqueous (A) and a detergent (D) phase. The
immunoblots were probed with anti-p25 antibody. Closed and open arrowheads
indicate p25 and p17, respectively.