Table 1. Induction of BlaPβ-lactamase of the BlaR1 L3 loop mutants.

	Mutation	Plasmids	Induction factor* (3h)
Wild type		pDML995	37.8±1.5
Mutants in H212EXXH motif	H212A/E213A/H216A	pDML1268	1.6±0.1
	E213A	pDML1269	1.2±0.1
	H212A/H216A	pDML1270	1.2±0.1
	H216A	pDML1271	1.27±0.01
	E213D	pDML1279	1.07±0.02
	E213Q	pDML1280	1.6±0.2
Mutants in putative Zn++ ligands	D221A	pDML1277	1.2±0.1
	E253A	pDML1273	1.2±0.3
	D257A	pDML1274	1.9±0.1
	E274A	pDML1275	33.9±0.9
Mutants in putative general base	Y 272A	pDML1278	1.1±0.1
Mutants in R304R cleavage site	R304A/R305A	pDML3045	7.6±1.7

^*The induction factor corresponds to the ratio between the β-lactamase quantity/A⁶⁰⁰ for induced culture and the β-lactamase quantity/A⁶⁰⁰ for uninduced culture.