The amino acid sequence of a major polypeptide chain of earthworm hemoglobin.
1982; Elsevier BV; Volume: 257; Issue: 15 Linguagem: Inglês
10.1016/s0021-9258(18)34233-9
ISSN1083-351X
Autores Tópico(s)Insect Utilization and Effects
ResumoThe amino acid sequence has been determined for polypeptide chain AI11 of the major component of the hemoglobin (erythrocruorin) from the earthworm, Lumbricus terrestris.The chain has 157 residues and a molecular weight of 17,496.Although the extent of sequence identity with other globin chains is only 17-1876, analysis of the sequence leads to the conclusion that the secondary structure of the chain i s very similar to those of vertebrate globins and that about 60-70% of the amino acid residues are in a helices.The D helix appears to be missing, as it is from the a chain of human hemoglobin and from the monomeric hemoglobin of Glycera dibranchiata, another annelid worm.This is the first sequence obtained from one of the "giant" extracellular hemoglobins of invertebrate animals.The extracellular hemoglobin from the earthworm, Lumbricus terrestris,, is a large multisubunit protein of molecular weight 2.5-3.9X lo6 (2-5).We have previously shown that the hemoglobin of both the major and minor components are each composed of three polypeptide chains with apparent molecular weights near 15-16,000 (6).We now report the amino acid sequence of one of these chains, AIII, from the major component.
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