Abstract
In the original version of this Article, Haoping Liu, who conceptualized, designed and supervised the project and acquired funding, was inadvertently omitted from the author list. Furthermore, the affiliation of Jiaxin Gao and Haoping Liu with 'Department of Biological Chemistry, University of California, Irvine, CA 92697, USA' was omitted. Finally, funding from NIH grant GM117111, and contributions from Dr. Li-lin Du of NIBS for providing pPB[ura4] and pDUAL-PBase and Allan Bradley of Sanger for hyPBase, were not acknowledged. These errors have now been corrected in both the PDF and HTML versions of the Article.