Primary structure and oxygen-binding properties of the hemoglobin from the lesser hedgehog tenrec (Echinops telfairi, Zalambdodonta). Evidence for phylogenetic isolation.

Summary: The primary structures of the a- and /3hemoglobin chains of the lesser hedgehog tenrec (Echinops telfairi, Zalambdodonta) are presented. Chain separation was performed by carboxymethyl­ cellulose chromatography. The peptides, obtained by tryptic digestion of the oxidized chains, were prefrac­ tionated by gel chromatography and isolated by re­ versed·phase HPLC. For sequence analysis gas and liquid phase sequencers were employed. The tenrec hemoglobin consists of one a- and two /3-chains the latter occurring in a 1: 1 ratio and differing in /316 Glyl Cys and /3118 PhelLeu. Two external cysteine residues at /316 and /352 cause reversible polymerization to oc­ tamers and most likely irreversible formation of higher polymers. A comparison of the whole chains and certain posi­ tions of tenrec hemoglobin with those of Insectivora sensu strictu, Scandentia and Proto- and Metatheria corroborates a long and independent evolution of ten­ rec and its phylogenetic isolation from the Insectivora s.str. (hedgehog, musk shrew and mole). Replacements at positions involved in heme and sub­ unit interface contacts are discussed. Compared to human hemoglobin the temec pigment shows a low intrinsic oxygen affinity as well as lower chloride and temperature sensitivities, a reduced Bohr effect and a strong response to 2,3-DPG. The possible adaptive significance of these properties is discussed in relation to the large diurnal body temperature variations seen in tenrecs. Primiirstruktur und Sauerstoffbindungs-Eigenschaften des Hiimoglobins vom Kleinen Igeltanrek (Echinops telfairi, Zalambdodonta) - Ein Hinweis auf phylogenetische Isolation Zusammenfassnng: Die Primarstruktur der a- und /3Ketten des Hamoglobins vom Kleinen Igeltanrek (Echinops telfairi, Zalambdodonta) wird angegeben. Die Ketten konnten durch Carboxymethylcellulose­ Chromatographie getrennt werden. Die nach der tryptischen Spaltung der oxidierten Ketten erhalte­ nen Peptide wurden zunachst durch Gelchromatogra­ phie vorfraktioniert und dann mit Hilfe von Rever­ sed-Phase-HPLC isoliert. Die Sequenzanalyse er­ folgte in Gas- und Fltissigphasen-Sequenatoren. Das Tanrek-Hamoglobin hat eine a- und zwei /3-Ketten.