Extreme divergence between one-to-one orthologs: the structure of N15 Cro bound to operator DNA and its relationship to the λ Cro complex.

ABSTRACT: The gene cro promotes lytic growth of phages through binding of Cro protein dimers to regulatory DNA sites. Most Cro proteins are one-to-one orthologs, yet their sequence, structure and binding site sequences are quite divergent across lambdoid phages. We report the cocrystal structure of bacteriophage N15 Cro with a symmetric consensus site. We contrast this complex with an orthologous structure from phage λ, which has a dissimilar binding site sequence and a Cro protein that is highly divergent in sequence, dimerization interface and protein fold. The N15 Cro complex has less DNA bending and smaller DNA-induced changes in protein structure. N15 Cro makes fewer direct contacts and hydrogen bonds to bases, relying mostly on water-mediated and Van der Waals contacts to recognize the sequenc

SUBMITTER: Hall BM 

PROVIDER: S-EPMC6649833 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature