Structure of the cooperative Xis-DNA complex reveals a micronucleoprotein filament that regulates phage lambda intasome assembly.

ABSTRACT: The DNA architectural protein Xis regulates the construction of higher-order nucleoprotein intasomes that integrate and excise the genome of phage lambda from the Escherichia coli chromosome. Xis modulates the directionality of site-specific recombination by stimulating phage excision 10(6)-fold, while simultaneously inhibiting phage reintegration. Control is exerted by cooperatively assembling onto a approximately 35-bp DNA regulatory element, which it distorts to preferentially stabilize an excisive intasome. Here, we report the 2.6-A crystal structure of the complex between three cooperatively bound Xis proteins and a 33-bp DNA containing the regulatory element. Xis binds DNA in a head-to-tail orientation to generate a micronucleoprotein filament. Although each protomer is anchored to t

SUBMITTER: Abbani MA 

PROVIDER: S-EPMC1893000 | biostudies-literature | 2007 Feb

REPOSITORIES: biostudies-literature