Ciliary adenosinetriphosphatase from a slow swimming mutant of Paramecium caudatum.

The slow swimming mutant (strain 11C 104), isolated from Paramecium caudatum, which swims at a speed about 70% of the wild type, is not different from the wild type (strain Kyky-1) in cell shape, density of cilia over the cell surface, and length of cilia. Cross-sectioned structures of the somatic cilia also do not give any difference between the mutant and the wild type. ATPase activities of ciliary axonemes and Tris/ EDTA extract from the mutant are found to be about 70% of those from the wild type. Sucrose density gradient centrifugation of the Tris/EDTA extract from the wild type suggests the presence of two ATPase enzymes in 14 S and 30 S regions each. The mutant shows considerably lower ATPase activity in the 14 S fraction, while the 30 S fraction shows similar activity to that from the wild type. The extent of reduction of the ATPase activity by the 14 S fraction coincides well with the decrease in the swimming speed of the mutant. In relatively high molecular weight polypeptide chains analyzed by SDS-polyacrylamide gel electrophoresis, the 30 S fraction from the mutant gives the same band pattern as that from the wild type showing the molecular weights of 388,000 and 380,000. The 14 S fraction from the mutant represents identical polypeptides of 380,000, 370,000, 360,000, and 340,000 with the wild type, and gives one differently migrated polypeptide whose molecular weight is 268,000 lower than the 280,000 present in the wild type.