| Budget Amount *help |
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1988: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1987: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Research 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). This hemoglobin was first studied in solution by small-angle X-ray scattering. The following molecular parameters were determined: radius of gyration 10.8 + 0.2 nm and a meximum interaparicular distance of 29.5 + 0.5 nm. Models which fit well the- experimental data and reflect also the biochemical structure especiallly the known number of polyoeotide chains are presented.
Furthermore, the sites of disulfide bonds in the trimer have been determined. In the trimer, threr are two interchain disulfide bonds between chains IIA and IIC, and IIB and IIC, respectively. In addition, each of the four chanis, 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 homoglobin. Digital image procecessing of saccnning transmission electron micrographs of negatively stained Tylorrhynchus hemoglobin indicated dimensions of 28 x 18 nm.
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