BIOMOLECULAR ASPECTS OF SPERMATOZOAN MOTILITY 



201 



extracts, acidified salt extracts and whole flagella, already referred to 

 and illustrated in Fig. 4/ as giving well-defined cross-/? diagrams, all 

 gave infrared absorption spectra with pronounced peaks at 1625 cm -1 . 

 The graphs shown in Fig. 5 compare the changes in the spectra of 

 flagellar protein and extracts with actin and myosin after exposure to 

 50% acetic acid vapor. The spectrum given by myosin after acidifica- 

 tion is about the same as that of all the proteins before treatment, and 

 the extent of the peak at 1625 cnr 1 from flagellar sources compares 

 with actin after similar treatment in acid vapor. The results suggest 

 that the bulk of the protein or proteins in the flagellum undergoes 

 marked changes after acid treatment, and in terms of muscle proteins 

 behaves more like actin than like myosin. 



SOME COMMENTS ON THE X-RAY DIFFRACTION AND INFRARED FINDINGS 



The reflection at 4.65 A on the meridian of x-ray diffraction dia- 

 grams was originally reported by Astbury et al. (1935) in heat-de- 

 natured egg albumin, but it was not until later that supercontraction 

 was considered in terms of transformation from the a-configuration to 

 the "jumping cracker" cross-/? form (see again Astbury et al., 1959, for 

 details). In other words, the crystallographic evidence for configura- 

 tional changes of the cross-^3 kind has been described for two kinds (or 



ACTIN 

 FLAGELLA 



— »>-50% H*S 



1600 

 CM' 1 l655 l625 



Fig. 5. Changes in the infrared absorption spectra of flagella, actin and 

 myosin after treatment in acid. 



