Peter E. Nute

Hemoglobinopathic Erythrocytosis due to a New Electrophoretically Silent Variant, Hemoglobin San Diego (β109(G11)Val→Met)

Examination of 13 members of a Filipino family revealed that 6 had erythrocytosis inherited as a simple autosomal dominant trait. Application of several electrophoretic and chromatographic tests failed to reveal the presence of an abnormal hemoglobin in hemolysates from affected individuals. However, measurements of oxygen dissociation curves using whole bloods, dialyzed hemolysates, and 2,3-diphosphoglyceric acid-stripped hemolysates clearly showed that affected persons had an abnormal hemoglobin characterized by a high affinity for oxygen. Compositional analyses of all tryptic peptides from the beta-chains of the proband revealed a valyl-methionyl ambiguity in betaT12a. Blockage of lysyl residues and subsequent tryptic hydrolysis at arginyl residues permitted the isolation of fragments containing residues 105 through 146. Automatic sequence analysis of the fragments demonstrated the presence of both valine and methionine in nearly equal proportions at position beta109. This new hemoglobin variant is designated Hb San Diego (beta109(G11) Val-->Met).

Hemoglobin Olympia (β20 Valine → Methionine): An Electrophoretically Silent Variant Associated with High Oxygen Affinity and Erythrocytosis

In a family with erythrocytosis, electrophoretic and chromatographic studies failed to demonstrate a hemoglobin variant. However, the oxygen dissociation curves of affected individuals were shifted to the left of normal and this shift persisted when oxygen equilibria were studied in 2.3-diphosphoglycerate-stripped hemolysates. A mutant hemoglobin was evidently present in the red blood cells of the affected persons and was responsible for the increased oxygen affinity and erythrocytosis. Specific staining of tryptic peptide maps of beta-chains from the propositus showed that peptide betaT(3) was positive for a sulfur-containing amino acid. Amino acid analysis yielded a composition identical to that of normal betaT(3), except that there were 2.6 residues of valine and 0.4 residues of methionine (normal composition: Val = 3.0, Met = 0). This suggested that the beta-chains of affected individuals consisted of a mixture of two kinds of chains, 40% of which had a methionyl residue in betaT(3). Structural studies of isolated cyanogen bromide fragments demonstrated unequivocally that, in the abnormal beta-chains, valine in position 20 is replaced by methionine. The new hemoglobin mutant is designated hemoglobin Olympia (beta20 (B2) valine --> methionine).

MULTIPLE HEMOGLOBIN α-CHAIN LOCI IN MONKEYS, APES, AND MAN *

Evidence for the presence of multiple hemoglobin a-chain loci exists for several primate species. However, interpretations of the results of many studies are handicapped by a lack of knowledge of linkage relationships among these loci. Furthermore, in no case are multiple a-chain loci known to be present in all members of any population of primates examined to date. Although direct proof of multiple a-chain loci is unavailable for many primate species, one can base an argument for their existence on comparisons of the phenotypes of animals whose genotypes are in question with those derived from studies of animals in which multiple loci are known to occur. The major objectives of this study include the construction of a genetic model that can be used to explain the distributions of hemoglobin phenotypes among populations of human and nonhuman primates, and the interpretation of data concerning multiple a-chain loci among the Anthropoidea in an evolutionary context.

Somatic-Cell Mutation Monitoring System Based on Human Hemoglobin Mutants

The system described in this chapter was developed as a means of detecting rare red cells, in genetically normal (HbA/HbA) individuals, that are heterozygous for an abnormal hemoglobin. It is assumed, first, that mutations arise spontaneously in human hemopoietic stem cells, as they do in gametal stem cells, and second, that somatic mutations of globin-chain genes do not diminish the viability of affected stem cells. The latter assumption is a reasonable one, since phenotypic expression of such mutations occurs very late in hemopoietic cell differentiation. It is expected that as a result of these stem cell mutations, lines of stem cells containing the mutant globin genes are established and produce erythrocytes heterozygous for structurally abnormal globin chains. Development of appropriate methods of screening blood samples should then permit detection and enumeration of red cells that contain an abnormal hemoglobin as a result of somatic mutation in a stem cell.

Complete Primary Structure of the 3 Chain From the Hemoglobin of a Baboon, Papio cynocephalus

The complete primary structure of the beta chain from the adult hemoglobin of a baboon, Papio cynocephalus, has been determined by automated, Edman degradation of the intact chain and four fragments derived therefrom by specific cleavage reactions. The analysis was facilitated by application of a modified solvent system that permits unambiguous identification, by high-performance liquid chromatography, of the 17 amino acids whose phenylthiohydantoin derivatives are soluble in ethyl acetate. The sequence obtained differs from that of the human beta chain at eight sites, a degree of divergence similar to that observed when human and macaque beta chains are compared. Of the cercopithecoid beta chains whose complete sequences have been determined or inferred from compositions of small peptides, that of P. cynocephalus is most like the beta chain of the gelada baboon, an observation in accord with assessment of a close phylogenetic relationship between the genera Papio and Theropithecus.

Hemoglobin α-chain variation in macaques: Primary structures of the αI and αII chains from the adult hemoglobins of Malaysian Macaca nemestrina

Abstract The complete primary structures of each of the two α chains commonly found in the adult hemoglobins of Malaysian Macaca nemestrina (pig-tailed macaques) were obtained from the intact chains and five fragments produced by two nonenzymatic and three enzymatic cleavage reactions. The two chains differ at a single site, the α I chains having a glutaminyl residue and the α II chains having a histidinyl residue in position 78. Both chains differ from their human counterpart at five positions, the extent of divergence being similar to that observed for most of the α chains from other species of Macaca that have been analyzed to date. Elucidation of the structural difference between the α I and α II chains demonstrates that the high degree of heterogeneity observed among the hemoglobin phenotypes of M. nemestrina is a consequence of underlying genetic variability and not a result of postsynthetic modification of genetically identical proteins. Comparisons with the hemoglobin phenotypes found in other species of Macaca support the contention that chromosomes bearing linked α I and α II genes, as well as those bearing single α I and α II alleles, combine in zygotes to produce the phenotypic variation observed in members of Malaysian populations of M. nemestrina .

Primate hemoglobins: their structure, function and evolution. I. Amino acid compositions of the tryptic peptides from the beta chain of Cebus albifrons.

Abstract 1. 1. Two fragments were isolated after cyanogen bromide cleavage of the aminoethylated β chain from the major hemoglobin of a New World monkey ( Cebus albifrons ). Each fragment was digested with trypsin and the resulting peptides were isolated. The peptides were placed in sequence by homology with the corresponding peptides from the human β chain. The locations of residues that differ from those in the human β chain were deduced from analyses of the thermolysin peptides produced by subfragmentation of selected tryptic peptides. The β chain of C. albifrons differs from that of man at a minimum of seven positions; in addition, two residues (threonine and alanine) were found at position 13. 2. 2. Comparison with β chains from other New World monkeys, Old World monkeys and apes indicates that the ceboid β chains comprise a related group of polypeptide chains which are more similar to those of cercopithecoids than they are to those of hominoids.

Complete Sequence of the γ Chain from the Fetal Hemoglobin of the Baboon, Papio cynocephalus

The amino acid sequence of the hemoglobin γ chain from a baboon, Papio cynocephalus, was determined by automated sequencing of the intact chain and six fragments generated by specific cleavage reactions. the existence of structural heterogeneity at position 75, where both valyl and isoleucyl residues were found, is suggestive of the presence of nonallelic Vγ and Iγ-chain genes in this species, and further emphasizes the extent to which the genetic basis of hemoglobin production among many higher primates is similar. Comparison of the sequences of those γ chains from Homo sapiens, Pan troglodytes, Macaca nemestrina and P. cynocephalus that have been well characterized attests to the conservative nature of γ-chain evolution among the Anthropoidea, the differences in sequence between any two of these chains ranging from none (between the Aγ and Gγ chains of P. troglodytes and H. sapiens) to no more than five (between the Vγ chains of p. cynocephalus and the Aγ chains of H. sapiens).

Hemogloblin α-gene duplication in macaques: Individual Macaca nemestrina with three structurally different α chains

Abstract The diversity of hemoglobin phenotypes observed among Malaysian Macaca nemestrina (pig-tailed macaques) has been attributed, in part, to the presence of duplicated α-chain loci in some members of this species. To date, evidence in support of this view has been indirect, consisting of variation in proportions of α I (Asp 71 , Gln 78 ) and α II (Asp 71 , His 78 ) chains among presumptive heterozygotes. However, the discovery that erythrocytes from some M. nemestrina contain α I and α II chains in company with a third, or α III , chain (Gly 71 , Gln 78 ) provides direct evidence of duplicated α-chain loci.

Structure and Function of Baboon Hemoglobins

This chapter details some preliminary findings concerning the structural and functional properties of hemoglobin from the olive baboon, Papio cynocephalus (= anubis). Although the amino acid sequence characterizations are not com-plete, nevertheless they do locate many of the presumed interchanges and even at this stage may possibly contribute to our understanding of human and primate hemoglobins.