Prompted by the reported lack of solvation effects on the oxygen affinity of fish (trout I) hemoglobin that questioned allosteric water binding in human hemoglobin A (Bellelli, A., Brancaccio, A., and Brunori, M. (1993) J. Biol. Chem. 268, 4742-4744), we have investigated solvation effects in fish and human hemoglobins by means of the osmotic stress method and allosteric analysis. In contrast t...

The effect of pH and inositol hexaphosphate (IHP) on the symmetry of the heme environments in opossum (Didelphius marsupialis) and new Zealand White rabbit hemoglobins has been studied using electron spin resonance (ESR). Each methemoglobin is found to contain two different heme environments as detected by the rhombicity observed in the ESR spectrum. In both cases the rhombic nature of the ESR ...

Oxygen-transport proteins are multisubunit, circulating molecules that provide an efficient supply of oxygen to metabolically active metazoans. Hemoglobins, hemerythrins and hemocyanins have evolved in both structural and functional diversity and exhibit functional repertoires beyond that of simple, monomeric tissue myoglobins. Their phylogenetic distribution is intriguing, especially with resp...

The nuclear genome of the model organism Chlamydomonas reinhardtii contains genes for a dozen hemoglobins of the truncated lineage. Of those, THB1 is known to be expressed, but the product and its function have not yet been characterized. We present mutagenesis, optical, and nuclear magnetic resonance data for the recombinant protein and show that at pH near neutral in the absence of added liga...

Hbs are widely distributed in higher plants, and by comparing sequences, expression patterns, and ligand-binding properties, it is evident that these fall into two broad groups (Fig. 1; also see Andersson et al., 1996). The symbiotic-type Hbs are predominantly found in the infected cells of nitrogen-fixing nodules of legumes and nonlegumes and function to facilitate oxygen transport. The other ...

Negative selection against protein instability is a central influence on evolution of proteins. Protein stability is maintained over evolution despite changes in underlying sequences. An empirical all-site stability-based model of evolution was developed to focus on the selection of residues arising from their contributions to protein stability. In this model, site rates could vary. A structure...

Hemoglobin Rainier (beta(145) tyrosine-->histidine) is an abnormal hemoglobin associated with increased oxygen affinity, decreased heme-heme interaction, presence of a Bohr effect, and erythrocytosis, but without obvious clinical sequelae. Regulation of erythropoiesis was studied in affected members of families having either hemoglobin Rainier or Yakima, abnormal hemoglobins associated with ery...