University of Texas at El Paso El Paso, Texas, United States
Priyanka Gade (University of Texas at El Paso)| Amanda Erlandson (University of Illinois Urbana-Champaign)| Irimpan I. Mathews (Standford Synchrotron Radiation Light Source)| Xi Chen (Northwest University)| Paola Mera (University of Illinois Urbana-Champaign)| Chu-Young Kim (University of Texas at El Paso)
Echinomycin is a nonribosomal peptide antibiotic that acts by intercalating double-stranded DNA. The echinomycin biosynthetic gene cluster of Streptomyces lasaliensis contains a gene of unverified function, ecm16. We show that expression of Ecm16 in the echinomycin-sensitive E. coli K12 renders cells resistant to echinomycin. Additionally, we have determined the X-ray crystal structure of Ecm16 at 2.0 Å resolution. Interestingly, the three-dimensional structure of Ecm16 resembles that of UvrA, the DNA damage sensor protein from the prokaryotic nucleotide excision repair pathway. Ecm16, like UvrA, contains two nucleotide binding domains on a single polypeptide chain, and it can bind double-stranded DNA. However, our results show that neither UvrA nor Ecm16 can complement each other’s function in vivo.