| Autor: |
KORTT, Alexander A., TRINICK, Michael J., APPLEBY, Cyril A. |
| Zdroj: |
European Journal of Biochemistry; 7/1/88, Vol. 175 Issue 1, p141-149, 9p, 2 Diagrams, 4 Charts, 2 Graphs |
| Abstrakt: |
The amino acid sequence of hemoglobins I (PI 6.15 as oxyhemoglobin) and II (PI 5.64 as oxyhemoglobin) from the nitrogen-fixing root nodules of Parasponia rigida have been determined by protein sequencing. The sequence of hemoglobin I (PI 6.16, as oxyhemoglobin) from Parasponia andersonii was re-examined and the corrected primary structure, now in agreement with that predicted from the DNA sequence, is reported. The three Parasponia hemoglobins contain 161 amino acid residues (Mr ≈ 18700 including the heme) with a single cysteine residue and five methionine residues. The N-terminal serine is blocked by an acetyl group. The primary structure of the Parasponia hemoglobins is highly conserved. Hemoglobins I from the two species of Parasponia are identical; both show microhetereogeneity at position 30 (Asp/Glu substitution) and hemoglobin I fom P. rigida shows microheterogeneity at position 150 (Ala/Val) while hemoglobin I from P. andersonii has only an Ala at 150. P. rigida hemoglobin II shows no microheterogeneity at these positions, having Asp and Val residues respectively, and it contains a single amino acid change of a Gln for an Arg at position 85, which accounts for the 0.5 unit difference in isoelectric point observed between hemoglobins I and II. The sequence data are consistent with allelic heterogeneity at a single locus rather than different genes. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
