Table 1.
Alignment of the I-helix sequence around the highly conserved threonine in various P450s.
These sequences show the highly conserved threonine, represented with the bold T and surrounding sequences in selected P450s from bacteria and mammals (6,15). The conserved glutamic acids in the CYP4 family, which have been demonstrated to be required for heme cross-linking to these proteins (46) are represented with the bold E.
| Protein | Partial I-helix sequence | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| P450cam | L | L | L | V | G | G | L | D | T | 252 | V | V | N | F | L | S |
| P450 BM3 | T | F | L | I | A | G | H | E | T | 268 | T | S | G | L | L | S |
| P450 1A2 | D | I | F | G | A | G | F | E | T | 319 | V | T | T | A | I | F |
| P450 2B4 | S | L | F | F | A | G | T | E | T | 302 | T | S | T | T | L | R |
| P450 2E1 | D | M | F | F | A | G | T | E | T | 303 | T | S | T | T | L | R |
| P450 4A3 | T | F | M | F | E | G | H | D | T | 322 | T | A | S | G | I | S |
| P450 4F4 | T | F | M | F | E | G | H | D | T | 332 | T | A | S | G | L | S |