title: Novel S-S loops in the giant hemoglobin of Tylorrhynchus heterochaetus.
abstract: The extracellular hemoglobin of the polychaete Tylorrhynchus heterochaetus is a "giant" multisubunit protein consisting of two types of subunits: a "monomeric" chain (chain I) and a disulfide bonded "trimer" of chains IIA, IIB, and IIC. We have reported the complete amino acid sequences of all four chains (Suzuki, T., and Gotoh, T. (1986) J. Biol. Chem. 261, 9257-9267). The sites of disulfide bonds in the trimer have now been determined. In the trimer, there are two interchain disulfide bonds between chains IIA and IIC, and IIB and IIC, respectively. In addition, each of the four chains, I, IIA, IIB, IIC, has an intrachain disulfide bond. Thus, according to our "192-chain" model (Suzuki, T., and Gotoh, T. (1986) J. Mol. Biol. 190, 119-123), there are 288 disulfide bonds in Tylorrhynchus hemoglobin. Digital image processing of scanning transmission electron micrographs of negatively stained Tylorrhynchus hemoglobin indicated dimensions of 28 x 18 nm.
authors.affiliation: Department of Biology, Faculty of Science, Kochi University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
authors.forename: O H
authors.initials: OH
authors.lastname: Kapp
authors.forename: T
authors.initials: T
authors.lastname: Gotoh
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004220:Disulfides / Q000032:analysis; D006454:Hemoglobins / Q000302:isolation & purification; D046911:Macromolecular Substances; D011077:Polychaeta / Q000378:metabolism*; D011487:Protein Conformation
chemical_list: D000596:Amino Acids; D004220:Disulfides; D006454:Hemoglobins; D046911:Macromolecular Substances