BACTERIOPHAGE-HK97 HEAD ASSEMBLY

The head assembly pathway of bacteriophage HK97 shares many features w ith head assembly pathways determined for other dsDNA phages, and it a lso provides examples of novel variations on the basic theme. We descr ibe aspects of two specific steps in the assembly pathway, the covalen t cross-linking among the assembled head protein subunits and the clea vage of those subunits that takes place earlier in the pathway. Compar isons of head assembly pathways among different phages, as well as com parisons of the organization of the genes that specify those pathways, suggest the range of different solutions phages have found to common assembly problems and give insight into the evolutionary histories of these assembly processes.