S. Liotenberg et al., MODIFICATION OF THE P-II PROTEIN IN RESPONSE TO CARBON AND NITROGEN AVAILABILITY IN FILAMENTOUS HETEROCYSTOUS CYANOBACTERIA, FEMS microbiology letters, 144(2-3), 1996, pp. 185-190
In the filamentous cyanobacterium Calothrix PCC 7504, which fixes N-2
aerobically, the modification state of the regulatory P-II protein (Gl
nB) was shown to depend on nitrogen and carbon availability, as observ
ed in the unicellular non-fixing strain Synechococcus PCC 7942. Howeve
r, the conditions for modifications, the time dependence of the proces
s and the electrophoretic behavior of the native P-II isoforms differe
d somewhat between the two strains. In another strain, Calothrix PCC 7
601, which has lost the capability to fix N-2, P-II was modified only
if ammonia plus an inhibitor of glutamine synthetase were present. It
is proposed that: (i) the behavior of the P-II proteins depends upon t
he physiological properties of the strains; and (ii) the modification
system of P-II per se may differ between the two cyanobacterial genera
.