TABLE 1.

Summary of the point mutations in ftsL and ftsB^a

Mutations	Complementationb	DN	Relative strength of DNc	Suppression of DN by E88Kc	Suppression of DN by FtsN expressiond
FtsL mutations
L24K	NT	Weak	+	NT	NT
L24K, I28K	No	Yes	++	NT	NT
R61C	NT	Weak	+	NT	NT
R61E	No	Yes	++	Yes	Yes
L77K	NT	No
D78K	NT	No
E80K	NT	No
W81A	NT	No
R82E	No	Yes	+++	NT	NT
N83K	No	Yes	+++	Yes	NT
L84K	No	Yes	+++	NT	NT
L86F	No	Yes	++++	No	No
E87K	No	Yes	++++	No	No
A90E	No	Yes	+++	Yes	Yes
L91K	Yes	No
R96E	Yes	No
A101K	Yes	No
L105D	Yes	No
M107K	Yes	No
E115K	Yes	No
P112-Stop	Yes	No
Q114-Stop	Yes	No
FtsB mutationse
N43K	Yes	No
N50Kf	No	No
Q52K	Yes	No
F54K	Yes	No
I57K	Yes	No
L60K	Yes	No
A66K	Yes	No

^aDN, dominant negative.

^bNT, not tested. Complementation and suppression tests were done in strain SD399.

^cIndicates IPTG concentration that inhibited colony formation: ++++, 25 μM; +++, 30 μM; ++, 50 to 100 μM; +, cells filamentous at 100 μM. Dominant negative tests were done in JS238 with derivatives of pKTP100 (P_tac::ftsL) and pKTP101 (P_tac::ftsB) carrying the indicated mutations.

^dSuppression by ftsN was done with strain SD399 (pSD256) containing plasmids pSD296 (ftsL^m) and pSEB417 (ftsN).

^eFor these strains, complementation was done using strain BL155/pBL194.

^fIt is likely that this mutant is unstable.