Purealin Blocks the Sliding Movement of Sea Urchin Flagellar Axonemes by Selective Inhibition of Half the ATPase Activity of Axonemal Dyneins
| Autor: | Yang-Il Fang, Hideshi Nakamura, Yasushi Ohizumi, Etsuo Yokota, Issei Mabuchi |
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| Rok vydání: | 1997 |
| Předmět: |
Male
Axoneme Octoxynol ATPase Dynein Motility Flagellum Biochemistry biology.animal Animals Enzyme Inhibitors Sea urchin Adenosine Triphosphatases Binding Sites Photolysis Molecular Structure biology Chemistry Cell Membrane Dyneins Anatomy Sperm Porifera Kinetics A-site Sea Urchins Sperm Tail Sperm Motility biology.protein Biophysics Electrophoresis Polyacrylamide Gel Vanadates Bromobenzenes |
| Zdroj: | Biochemistry. 36:15561-15567 |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi971363n |
| Popis: | Ciliary and flagellar movements are explained by active sliding between the outer doublet microtubules of an axoneme via their inner and outer dynein arms. Purealin, a novel bioactive principle of a sea sponge Psammaplysilla purea, blocked the motility of Triton-demembranated sea urchin sperm flagella within 5 min at concentrations above 20 microM. In a similar concentration range, purealin blocked the sliding movement of the flagellar axonemes in vitro within a few minutes judging from the turbidity measurements. The ATPase activity of axonemes was partially inhibited by purealin in a concentration-dependent manner. The maximum inhibition reached approximately 50% at concentrations above 20 microM, indicating that half the axonemal ATPase activity is sensitive to purealin. Similar results were observed on the ATPase activity of outer-arm-depleted axonemes and that of a mixture of 21S dynein and salt-extracted axonemes. On the other hand, ATPase activity of isolated 21S dynein was not inhibited by purealin. The inhibitory action of purealin on the axonemal ATPases was reversed by dilution of purealin. The effect of purealin on the double-reciprocal plot of the ATPase activity as a function of ATP concentrations showed that the inhibition was not a competitive type. In accord with this finding, purealin did not affect the vanadate-mediated UV photocleavage of axonemal dyneins. These results suggest that purealin binds reversibly to a site other than the catalytic ATP-binding site and inhibits half the ATPase activity of axonemes. Taken together, our results suggest that purealin-sensitive ATPase activity of the dynein arms plays an essential role in generating the sliding movement of flagellar axonemes. |
| Databáze: | OpenAIRE |
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