A protein constructed de novo enables cell growth by altering gene regulation. Author Katherine Digianantonio, Michael Hecht Publication Year 2016 Type Journal Article Abstract Recent advances in protein design rely on rational and computational approaches to create novel sequences that fold and function. In contrast, natural systems selected functional proteins without any design a priori. In an attempt to mimic nature, we used large libraries of novel sequences and selected for functional proteins that rescue Escherichia coli cells in which a conditionally essential gene has been deleted. In this way, the de novo protein SynSerB3 was selected as a rescuer of cells in which serB, which encodes phosphoserine phosphatase, an enzyme essential for serine biosynthesis, was deleted. However, SynSerB3 does not rescue the deleted activity by catalyzing hydrolysis of phosphoserine. Instead, SynSerB3 up-regulates hisB, a gene encoding histidinol phosphate phosphatase. This endogenous E. coli phosphatase has promiscuous activity that, when overexpressed, compensates for the deletion of phosphoserine phosphatase. Thus, the de novo protein SynSerB3 rescues the deletion of serB by altering the natural regulation of the His operon. Keywords Escherichia coli, Gene Expression Profiling, Transcription, Genetic, Escherichia coli Proteins, Operon, Phosphoric Monoester Hydrolases, Hydrolysis, Biocatalysis, Culture Media, SOS Response, Genetics Journal Proc Natl Acad Sci U S A Volume 113 Issue 9 Pages 2400-5 Date Published 2016 Mar 01 ISSN Number 1091-6490 DOI 10.1073/pnas.1600566113 Alternate Journal Proc Natl Acad Sci U S A PMCID PMC4780649 PMID 26884172 PubMedPubMed CentralGoogle ScholarBibTeXEndNote X3 XML