Table 1.

Growth interference and suppression by mutations in the tripeptide anticodon and domain C of E. coli RF2

Pep-anticodon change	IPTG	Effect on cell growth of domain C change
		Wild type	E149K	E157K	E167K	E170K
Wild type	−	++	++	++	++	++
	+	++	++	++	++	++
R200A	−	++	++	++	++	++
	+	−	++	+	+	+
S205P	−	++	++	++	++	++
	+	−	++	++	++	++
P206A	−	++	++	++	++	++
	+	−	++	++	++	++
F207T	−	++	++	++	++	++
	+	−	++	++	++	++
R213I	−	++	++	++	++	++
	+	−	++	++	++	++
F217A	−	++	++	++	++	++
	+	−	++	++	++	++

The variant RF2 genes containing the indicated changes in the tripeptide anticodon and domain C were cloned in a lac promoter-controlled expression plasmid (pSUIQ) and transformed into wild-type E. coli (W3110). The growth of Cm^R transformants was monitored at 32°C on YT agar plates (1% bacto-tryptone, 0.1% yeast extract, and 0.25% NaCl) in the presence (i.e., expression of variant RF2 proteins) or absence (i.e., no expression of variant RF2 proteins) of 1 mM IPTG. ++, normal growth; +, slow growth; −, no growth (i.e., growth interference).