SecY alterations characterized in this study
| Allele name . | Amino acid change . | Domain affected . | OmpA export . | MalF-PSBT insertion . | Cpx/σE stress . | LacY folding . | LacY stability . |
|---|---|---|---|---|---|---|---|
| secY+ | None | None | + | + | – | + | + |
| secY125a | S76Fa | P1 (TM2a) | – | – | + | – | – |
| secY124, secY84ab | P84La | TM2 | – | – | + | NT | NT |
| secY238ab | E238Ka | TM6/C4 | (+) | – | + | – | – |
| secY299b | G299D | P4 | (+) | – | (−) | NT | NT |
| secY351ab | A351Ta | C5 | (+) | – | + | NT | NT |
| secY39 | R357H | C5 | – | + | – | + | + |
| secY40 | A363T | C5 | (+) | – | (−) | + | + |
| secY129a | C385Ya | TM9 | (+) | – | + | – | – |
| secY403b | G403R | TM10 | (+) | – | (−) | NT | NT |
| secY205 | Y429D | C6 | – | + | – | + | + |
| rplO215 | None (low abundance) | None (low abundance) | – | – | – | NT | NT |
| Allele name . | Amino acid change . | Domain affected . | OmpA export . | MalF-PSBT insertion . | Cpx/σE stress . | LacY folding . | LacY stability . |
|---|---|---|---|---|---|---|---|
| secY+ | None | None | + | + | – | + | + |
| secY125a | S76Fa | P1 (TM2a) | – | – | + | – | – |
| secY124, secY84ab | P84La | TM2 | – | – | + | NT | NT |
| secY238ab | E238Ka | TM6/C4 | (+) | – | + | – | – |
| secY299b | G299D | P4 | (+) | – | (−) | NT | NT |
| secY351ab | A351Ta | C5 | (+) | – | + | NT | NT |
| secY39 | R357H | C5 | – | + | – | + | + |
| secY40 | A363T | C5 | (+) | – | (−) | + | + |
| secY129a | C385Ya | TM9 | (+) | – | + | – | – |
| secY403b | G403R | TM10 | (+) | – | (−) | NT | NT |
| secY205 | Y429D | C6 | – | + | – | + | + |
| rplO215 | None (low abundance) | None (low abundance) | – | – | – | NT | NT |
In the third column, SecY domains are indicated by TM, C, and P for transmembrane, cytoplasmic, and periplasmic domains, respectively, numbered from the N terminus in this order. In the fourth and fifth columns, – indicates a considerable defect, + indicates no defect, and (+) indicates a weak defect. In the sixth column, + indicates considerable induction, – indicates no induction, and (−) indicates weak induction. In the seventh column, + and − indicate normal and defective folding, respectively. In the last column, + and − indicate normal and decreased stability, respectively. NT, not tested.
Stress response inducers, which are referred to as membrane protein folding–defective mutants in this paper.
Mutations newly identified in this study by the stress response–based screening described in Materials and methods. The rplO215(amber) mutation reduces the expression level of SecY.