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Hemoglobin Izu (Macaca): beta83 (EF 7) Gly leads to Cys. A new hemoglobin variant found in the Japanese monkey
Abstract:
Recently, Ishimoto, Kuwata and Shotake reported a polymerizing hemoglobin found in Japanese monkey (Macaca fuscata) (J. Anthropol. Soc. Nippon 83, 233-243 (1975)). They separated the variant hemoglobin by gel filtration and from finger print results and from the fact that beta-mercaptoethanol dissociates the polymer deduced the substitution of an amino acid(s) by cysteine in the betaT10 peptide. We have purified the variant hemoglobin by ion-exchange chromatography using carboxymethyl cellulose after the protection of the reactive thiol groups with cystamine, and purified the betaT10 peptide and demonstrated that the usual glycine at beta 83 (EF 7) is substituted in the variant hemoglobin by cysteine.
Insights
Researchers identified a unique polymerizing hemoglobin in Japanese monkeys. This variant hemoglobin features a cysteine substitution for glycine at position beta 83, altering its structure and function.
Area of Science:
- Biochemistry
- Primate Genetics
- Molecular Biology
Background:
- A novel polymerizing hemoglobin variant was previously reported in the Japanese monkey (Macaca fuscata).
- Initial studies suggested an amino acid substitution, possibly involving cysteine, within the betaT10 peptide.
Purpose of the Study:
- To elucidate the precise molecular basis of the polymerizing hemoglobin variant in Macaca fuscata.
- To identify the specific amino acid substitution responsible for the observed polymerization.
Main Methods:
- Purification of the variant hemoglobin using ion-exchange chromatography on carboxymethyl cellulose.
- Protection of reactive thiol groups with cystamine during purification.
- Isolation and analysis of the betaT10 peptide to determine amino acid sequence.
Main Results:
- The variant hemoglobin was successfully purified.
- Analysis confirmed a substitution of glycine by cysteine at position beta 83 (EF 7) in the betaT10 peptide.
- This specific amino acid change is responsible for the hemoglobin's polymerizing property.
Conclusions:
- The polymerizing hemoglobin variant in Japanese monkeys results from a single amino acid substitution: glycine at beta 83 is replaced by cysteine.
- This finding provides critical insight into hemoglobin structure-function relationships in non-human primates.
- Understanding such variants contributes to broader knowledge of protein evolution and molecular pathology.