Acknowledgments

This work was supported by Public Health Service grants GM15590 and GM31667 from the National Institutes of Health and National Science Foundation grant PCM 8317682 to S.K.

We are most grateful to J.Williams for providing plasmid pJW1，to P.Kiley for providing cloned KpnI-PstI，AluI，PvuII-SalI，and XhoI-NruI fragment DNA，and to P.Hallenbeck for providing plasmid pLI10，C-2-C DNA，and the internal Pst DNA fragment.We thank T.J.Donohue for making［γ-32P］ATP and W.D.Sheperd for his technical assistance.We especially thank S.Kuhl for providing plasmid pUI135 and pUI128 DNAs as well as for his helpful discussion and comments during the writing of this paper.(https://www.daowen.com)