title: The first sequenced normal hemoglobin lacking histidine in position 146 of the beta-chains. The primary structures of the major and minor hemoglobin components of the great crested newt (Triturus cristatus, Urodela, Amphibia).
abstract: The hemoglobin of the Great Crested Newt (Triturus cristatus), an animal maintaining the gas exchange to about 85% through the skin, consists of a major (HbM = 65%) and a minor (Hbm = 35%) component. The primary structures of the four chains are presented. They could be separated by reversed-phase HPLC and were cleaved with trypsin and additionally by acid hydrolysis. Both the native chains and their peptides were sequenced by liquid and gas phase sequenators. At the N-terminus the alpha M-chains are by one amino-acid residue longer and the beta M-chains by one residue shorter, resulting in a chain length of 142 and 145, respectively. The alpha m-chains are of normal length whereas in the beta m-chains the C-terminal histidine in position 146 is missing. Both alpha-chains differ by 50 residues (35.2%) and the beta-chains by 63 (43.2%). The alpha-chains were compared with those of other salamandroid hemoglobins. The difference to human hemoglobin is marked by 61 (43.3%) amino-acid substitutions in both alpha-chains and by 78 (53.4%) in both beta-chains. Numerous heme contacts and positions involved in the subunit interface are affected by replacements. The most interesting of them were studied by molecular modeling. The importance of the missing beta m-146(HC3)His and of the substitution of several amino-acid residues involved in the binding of organic phosphates is discussed with respect to the reduced Bohr effect of Triturus cristatus hemoglobin.
authors.affiliation: Max-Planck-Institut für Biochemie, Abteilung Proteinchemie, Martinsried bei München.
authors.forename: T
authors.initials: T
authors.lastname: Kleinschmidt
authors.forename: J G
authors.initials: JG
authors.lastname: Sgouros
authors.forename: G
authors.initials: G
authors.lastname: Braunitzer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003196:Computer Graphics; D005914:Globins / Q000302:isolation & purification; D006441:Hemoglobin A; D006454:Hemoglobins / Q000302:isolation & purification; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000302:isolation & purification; D011487:Protein Conformation; D013045:Species Specificity; D014319:Triturus / Q000097:blood*; D014357:Trypsin
chemical_list: D006454:Hemoglobins; D010446:Peptide Fragments; D005914:Globins; D006441:Hemoglobin A; D014357:Trypsin