Open AccessIsomeric Incorporation of the Haem into Monomeric Haemoglobins of Chironomus thummi thummi
Author(s) -
RIBBING Wilfried,
RÜTERJANS Heinrich
Publication year - 1980
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1980.tb04698.x
Subject(s) - chironomus , chemistry , imidazole , histidine , monomer , heme , stereochemistry , crystallography , biology , amino acid , biochemistry , larva , organic chemistry , botany , chironomidae , enzyme , polymer
With high‐resolution NMR spectroscopy it has been possible to detect various types of isomerisms in the monomeric component III of the haemoglobins of Chironomus thummi. In the component III prepared from commercially available larvae of Ch. thummi a chemical heterogeneity has been found to occur at the position E6 (Ile or Thr). The imidazole C‐2 proton resonance of the adjacent His‐E7 is split because of this alternative occupancy. From larvae of an inbreeding of the single subspecies Chironomus thummi thummi a component III material has been isolated in which the position E6 is occupied by one single amino acid. An additional isomerism of this haemoglobin III is produced by an isomeric incorporation of the haem group into the haem pocket. This isomerism has been established from the complex signal pattern of the mesoproton resonances of the diamagnetic ligated haemoglobin III. Other evidences of this isomerism have been obtained from an analysis of the high‐field proton resonances.