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PROPERTIES OF THE PROTEIN SUBUNIT OF CENTRAL-PAIR AND OUTER-DOUBLET MICROTUBULES OF SEA URCHIN FLAGELLA
The subunit protein has been isolated from the central-pair and outer-doublet microtubules of sea urchin sperm tails. Both proteins have a sedimentation constant of 6S and a molecular weight of 120,000. Both are converted to a 60,000 molecular weight species by denaturation in 6 M guanidine hydrochl...
Autores principales: | , |
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Formato: | Texto |
Lenguaje: | English |
Publicado: |
The Rockefeller University Press
1968
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2107488/ https://www.ncbi.nlm.nih.gov/pubmed/5664206 |
Sumario: | The subunit protein has been isolated from the central-pair and outer-doublet microtubules of sea urchin sperm tails. Both proteins have a sedimentation constant of 6S and a molecular weight of 120,000. Both are converted to a 60,000 molecular weight species by denaturation in 6 M guanidine hydrochloride and reduction with mercaptoethanol. The reduced-alkylated proteins have the same R(f) on disc electrophoresis, and the same amino acid composition, which is very similar to that of muscle actin. The central-pair protein has one binding site for colchicine per 120,000 g. Both proteins appear to have a guanine nucleotide binding site, but the ability to bind GTP in solution has been demonstrated only for the central-pair protein. Although 1 mole of guanine nucleotide is bound per 60,000 g to outer-doublet tubules, the protein obtained by dissolving the doublets at pH 10.5 has lost the guanine nucleotide-binding site and also shows little or no colchicine-binding activity. Comparison of the properties of the isolated protein with electron microscopic evidence on structure of microtubules suggests that the chemical subunit (M = 120,000) consists of two of the 40 A morphological subunits. |
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