Calcium-induced increase in the radius of gyration and maximum dimension of calmodulin measured by small-angle X-ray scattering

We have used solution small-angle X-ray scattering to characterize bovine brain calmodulin in the presence and absence of calcium. In the presence of calcium, calmodulin exists in solution as an elongated molecule with a radius of gyration of 21.5 A and a maximum vector length of approximately 62 A. These values are consistent with the dimensions recently determined for the crystal form of rat testis calmodulin. In the absence of calcium, the calmodulin molecule is shorter, the radius of gyration decreases to 20.6 A, and the maximum vector length decreases to approximately 58 A. This change in dimensions is consistent with an overall contraction of the protein through movement of the two lobes closer to each other upon removal of calcium from calmodulin.     

Relatively Benign Sickle-cell Anaemia in 60 Patients Aged Over 30 in the West Indies

A study in Jamaica of 60 patients with sickle-cell anaemia over the age of 30 years showed that most of them were in full-time employment. Pains in the bones or joints, leg ulceration, and jaundice were the most frequent types of presentation, but only two patients had a haemoglobin level consistently below 6 g./ 100 ml. Most of the patients were well developed and of average height, and, though the development of secondary sexual characteristics was delayed, there was an average of 2.6 pregnancies per patient. These findings suggest that the course is more benign than has been realized.