Table 1.
Amino acids lining the cavities in sperm whale Mb
| Heme cavity | Xe1 | Xe2 | Xe3 | Xe4 |
|---|---|---|---|---|
| Leu-29 | Leu-89 | Leu-72 | Trp-7 | Gly-25 |
| Phe-46 | His-93 | Leu-104 | Ile-75 | Ile-28 |
| His-64 | Leu-104 | Ile-107 | Leu-76 | Leu-29 |
| Val-68 | Phe-138 | Ser-108 | Gly-80 | Gly-65 |
| Ile-107 | Ile-142 | Leu-135 | His-82 | Val-68 |
| Heme | Tyr-146 | Phe-138 | Ala-134 | Leu-69 |
| Heme | Arg-139 | Leu-137 | Leu-72 | |
| Heme | Phe-138 | Ile-107 | ||
| Ile-111 |
Amino acids adjacent to cavities. Residues in boldface are conserved among most mammals as well as the human hemoglobin chains. Only two residues, Phe-43 and His-93, are conserved in all Mbs (30), while all listed residues except Ile-142 and Ile-28 are conserved among a list of 15 mammals that are identical over only 59% of the sequence. The tertiary structure is conserved.