Abstract
The giant extracellular hemoglobin (3,800 kDa) of the oligochaete Lumbricus terrestris consists of four subunits: a monomer (chain I), two subunits each of about 35 kDa (chains V and VI), and a disulfide-bonded trimer (50 kDa) of chains II, III, and IV. The complete amino acid sequence of chain I was determined: it consists of 142 amino acid residues and has a molecular weight of 16,750 including a heme group. Fifty-nine residues (42%) were found to be identical with those in the corresponding positions in Lumbricus chain II (Garlick, R. L., and Riggs, A. F. (1982) J. Biol. Chem. 257, 9005-9015); 45 (32%), 56 (40%), 44 (31%), and 45 (32%) residues were found to be in identical positions in the sequences of chains I, IIA, IIB, and IIC, respectively, of Tylorrhynchus heterochaetus hemoglobin (Suzuki, T., and Gotoh, T. (1986) J. Biol. Chem. 261, 9257-9267). When the sequences of all six annelid chains are compared, 18 invariant residues are found in the first 104 residues of the molecule; very little homology exists among the annelid chains in the carboxyl-terminal 38-residue region. Nine of the 18 invariant residues are also found in the human beta-globin chain.
Highlights
The giant extracellular hemoglobin (3,800kDa) of tenia (4) andmoinllusks(5).( d )Single-domainm, ultisubunit the oligochaeteLumbricus terrestris consistsof four hemoglobins,consistingof aggregatesof several small subsubunits: a monomer, two subunits each of units,someof which aredisulfide-bondedand noatll of which about 35 kDa, and a disulfide-bonded contain heme
Nine of the 18 narystructureis stabilized by the presenceof Ca2+(15)
Almost all oligochaeteand polychaetehemoglobinsexam- quencesof LumbricuschainsI11 and IV are shownin Table ined to date exhibit auniformunreduced sodium dodecyl sulfate-polyacrylamidegel electrophoresispattern: a mon
Summary
K. Fushitani and A. F. Riggs, personacl ommunication. found in carapacelessbranchiopod crustaceans such as Ar- Portions of this paper (including “Experimental Procedures,” from the United StatesPublic Health Service.The costsof publica- tosylamido-2-phenylethyl chloromethylketone;HPLC, high performtion of this article weredefrayed in partby the payment of page anceliquid chromatography;FPLC, fast protein liquid chromatogracharges.This article must therefore be herebymarked ‘‘advertise- phy; SDS,sodium dodecylsulfate; PTH, phenylthiohydantoin. Minment” in accordancewith 18 U.S.C.Section 1734solely to indicate iprint is easily read with the aid of a standard magnifying glass.Full this fact. sizephotocopiesare availablefrom the Journal of Biological Chemf Present address: Department of Biology, Nihon University, istry, 9650Rockville Pike, Bethesda,MD 20814. RequestDocument Schoolof Medicine, Tokyo 173Japan. Waverly Press. This is an Open Access article under tChCe BY license.
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