Table 3. Summary of effects of CfaA mutations on its interactions to CfaB subunit and pilus formation.
| Fimbriation | ||||
| Mutation Mean | CfaA/CfaB ratio | By heat extraction (p30) | By time-resolved MRHA (fprate) | Proposed function |
| Wild type | 0.66 | 100 | - | - |
| K9A | 0.64 | 45 | Delayeda | Function partially replaced by R154 |
| T44A/E45A/E46A | 0.67 | 43 | Delayeda | D1′ insertion, interacting with either subunit or usher |
| E86A | 0.32 | 25 | Minimal effect | Stabilizing R154 |
| T112A | 0.67 | 25 | No fimbriationb | P4: donor-strand exchange |
| L114A | 0.36 | 95 | No effect | P3: donor-strand complementation |
| V116A | 0.06 | 43 | Delayeda | P2: donor-strand complementation |
| I118A | 0.11 | 41 | Delayeda | P1: donor-strand complementation |
| Y120A | 0.13 | 10 | No fimbriationb | P0: donor-strand complementation |
| R125A | 0.47 | 65 | Minimal effect | Interaction with either subunit or usher |
| R154A | 0.44 | 95 | No effect | Replacing K9 for subunit interaction |
| C163S/C172S | 0.36 | 25 | Minimal effect | Disulfides stabilizing C2–D2′ loop. |
| K164-N171 (8×A) | 0.37 | 95 | Delayeda | C2–D2′ insertion for either subunit interaction or pilus assembly |
| ΔCfaA | 0.0 | 5 | No fimbriation | |
a
Wild type MRHA titer by 45 min.
b
Minimal to no MRHA detected through 60 min.