The 4 genes between capsid and tape measure (Corgi gp 8-11) include (in this order) head-to-tail adaptor, head-to-tail stopper, major tail, hypothetical protein. the hypothetical protein in these genomes hits HK97 gp10. Bob Duda of the Hendrix lab (who extensively has studied the structural genes of HK97) agrees the function of this gene, though structural, is unknown.