. Author manuscript; available in PMC: 2018 Feb 28.

Published in final edited form as: Biochemistry. 2017 Feb 16;56(8):1140–1150. doi: 10.1021/acs.biochem.6b01030

Table 2. Random mutagenesis of Ala501 in PBP2 revealed 5 amino acids that increase resistance to expanded-spectrum cephalosporins.

Transformants were selected at the indicated concentrations of cefixime, and the penA genes were amplified and sequenced. Data are from three independent transformations.

Cefixime concentration used for selection	Ala501 mutations	Number of isolates

0.1 μg ml⁻¹	Arg	21
	Ser	5
	Thr	20
	Val	18
	Pro	1

0.2 μg ml⁻¹	Arg	24