TABLE 3.
Alignment of the four motifs conserved in amino acid sequences of group 1 β-lactamasesa
| Source (β-lactamase) | Amino acid sequence at the following motif:
|
Refer- ence(s) | |||
|---|---|---|---|---|---|
| First | Second | Third | Fourth | ||
| E. coli | SVSK | YAN | DAEA | KTG | 7 |
| E. cloacae | SISK | YAN | DAQA | KTG | 3 |
| P. aeruginosa | SVSK | YSN | DAEG | KTG | 10 |
| K. pneumoniae (FOX-1) | SVSK | YSN | AAEA | KTG | 8 |
| C. freundii | SVSK | YAN | DAE(K)bA | KTG | 9, 22 |
| S. marcescens SR50 | 58-SLSK | 144-YSN | 211-DAES | 308-KTG | 15 |
| S. marcescens GN19450 (SST-1) | SLSK | YSN | DAES | KTG | This study |
| S. marcescens GN16694 (SRT-1) | SLSK | YSN | DAKS | KTG | This study |
a
The four motifs are in alignment from the upper position in their amino acid sequences.
b
In β-lactamases with the extended substrate specificity for oxyimino cephalosporins, E was substituted for K in the third motif.