Table 3.
Overview of Hsp104 variants
Based on the X-ray footprinting solvation data, Hsp104 variants were designed and purified. Their biochemical properties were then assessed by measuring ATPase activity, intrinsic disaggregase activity (ATP/ATPγS), and disaggregase activity in collaboration with Hsp40/Hsp70 pairs (Hdj2/Hsc70 or Hdj2/Hsp72). In this table ± indicates no significant difference from WT Hsp104; - denotes a statistically significant decrease in activity down to more than 60% WT Hsp104 activity; – denotes a statistically significant decrease down to 30–60% WT Hsp104 activity, and — denotes a statistically significant decrease to less than 30% of WT Hsp104 activity. Similarly, + signifies a statistically significant increase up to less than 150% WT Hsp104 activity; and ++ signifies a statistically significant increase greater than 200% WT Hsp104 activity. ND indicates not determined.
| Variant | Residues | Location | ATPase | Disaggregation |
|||
|---|---|---|---|---|---|---|---|
| ATP | ATP/ATPγS | Hdj2/Hsc70 | Hdj2/Hsp72 | ||||
| Hsp104-LVL | L92A/V95A/L96A | NTD | - | ± | — | - | ± |
| Hsp104-TYK | T87A/Y90A/K94A | NTD | ± | ± | – | — | – |
| Hsp104-QS | Q103A/S109A | NTD | ± | ± | - | – | ± |
| Hsp104-IK | I102A/K107A | NTD | ± | ± | – | — | ± |
| Hsp104-SS | S124A/S125A | NTD | ± | ± | ± | - | ± |
| Hsp104-TR | T8A/R10A | NTD | ± | ± | — | — | - |
| Hsp104-ED | E44R/D45R | NTD | ± | ± | + | + | ± |
| Hsp104-TM | T160M | NTD-NBD1 linker | – | ± | – | — | – |
| Hsp104-RRD | R148D/R152D/R156D | NTD-NBD1 linker | ± | ± | – | — | – |
| Hsp104-DDD | D231A/D232A/D233A | NBD1 | ± | ± | – | — | — |
| Hsp104-RYD | R496A/Y497A/D498A | NBD1 | + | ++ | — | – | – |
| Hsp104-N292A | N292A | NBD1 | ND | ND | — | ND | ND |
| Hsp104-K294A | K294A | NBD1 | ND | ND | – | ND | ND |
| Hsp104-D295A | D295A | NBD1 | ND | ND | — | ND | ND |
| Hsp104-P461A | P461A | MD | - | ± | – | — | - |
| Hsp104-P557L | P557L | MD | ± | ± | — | – | - |