(A) Cartoon of the predicted functional domains within SypF, including HAMP,
HisKA, HATPase_c, REC, and HPt domains (orange boxes) as well as transmembrane
regions (gray boxes) flanking a putative periplasmic loop. Conserved putative
sites of phosphorylation are indicated below in black type. SypF*
contains two mutations. The critical mutation, S247F, is indicated in pink type.
(B) Autoradiograph of purified MBP-SypF* (above) and wild-type MBP-SypF
(below) after incubation with unlabeled ATP or
[γ-32P]-ATP. (C) Colony morphology of
wild-type (WT) V. fischeri strain ES114 containing vector
control (VC, pKV69) or various SypF and SypF* overproduction plasmids as
follows: pSypF (pCLD54), pSypF* (pCLD29), pSypF*D549A (pANN61),
and pSypF*H705Q (pANN62). Cultures of the indicated strains were spotted
on agar plates and colony morphology was assessed after 24 h.