Table 1.
Sequences of A2 subdomains in this study.
| Full-Length (wt) | NEETQNLSTIYLRKYQSKVKRQIFSDYQSEVDIYNRIRNEL |
| Short A2 (A2s) | LTPEQVSKVKRQIFSDYQSEVDIYNRIRNEL |
| Medium A2 (A2m) | LTPEQVRKYQSKVKRQIFSDYQSEVDIYNRIRNEL |
| Long A2 (A2l) | LTPEQVIYLRKYQSKVKRQIFSDYQSEVDIYNRIRNEL |
| Short Cholera A2 (cA2s) | LTPEQVSKVKRQIFSGYQSDIDTHNRIKDEL |
| Medium Cholera A2 (cA2m) | LTPEQVRKYQSKVKRQIFSGYQSDIDTHNRIKDEL |
| Long Cholera A2 (cA2l) | LTPEQVIYLRKYQSKVKRQIFSGYQSDIDTHNRIKDEL |
| Medium A2 w/o N-Cap | RKYQSKVKRQIFSDYQSEVDIYNRIRNEL |
| Short Cholera A2 w/o N-Cap | SKVKRQIFSGYQSDIDTHNRIKDEL |
| Supershort Cholera A2 (cA2ss) | LTPEKRQIFSGYQSDIDTHNRIKDEL |
Residues from the wildtype A2 subdomain sequence observed making contacts to the LTI B subunit are in underline; helix N-capping motifs are bold; core sequence variations associated with CT are emboldened and underlined. The conserved C-terminal ER localization signal sequences RNEL/KDEL are not observed in any reported crystal structure, but they are essential for stable assembly with the B subunits34.