The functional mutation in an enzyme can confer resistance and retain its inhibitory activity. Interesting mutations of CEPA Beta-lactamase are identified that maintain the ability to hydrolyze cephalosporins and simultaneously show inhibitor resistance such as to aztreonam. CEPA shows a mutable frequency of 7.35% (20 out of 272 residues show a substitution mutation). A Mutational landscape was prepared with a target to identify mutational hotspots. The sequence of all 22 variants of CepA was compared against the Wild-type CepA_WT. This landscape gave a clear picture of the conserved sites and indicated any mutations if present in these regions. It also shows if more than one substitution has occurred at the same position in different variants. Our analysis showed that all the class A conserved sites were highly conserved among the CepA variants, and no mutations occurred in these regions. An average mutation of 2.2 is seen in CEPA variants

    CEPA Variant Substitution Mutation
    CEPA-1 G255R
    CEPA-2 V56I, T290aK, E88K, K171E
    CEPA-3 R284H, A257V
    CEPA-4 K171E
    CEPA-5 E88K, K171E, A257V
    CEPA-6 E88K, T111I, K171E
    CEPA-7 E88K, K171E, D245gE
    CEPA-8 A257V
    CEPA-9 V56I, Y79C, E88K, K171E, M231I
    CEPA-10 C16Y
    CEPA-11 E88K
    CEPA-12 E88K, T104bI, K171E
    CEPA-13 E88K, E196K, G253D
    CEPA-14 E28K, K171E, K196E, G245dA, D253S
    CEPA-15 T111I, K171E
    CEPA-16 E277K
    CEPA-17 E88K, T111I
    CEPA-18 E88K, K171E
    CEPA-19 D217G, A257V
    CEPA-20 E88K, H153N
    CEPA-21 V56I, E88K, K171E
    CEPA-22 E88K, K171E