Nature 367 (6465): 754-757 (1994)

DNA recognition by beta-sheets in the Arc repressor-operator crystal structure.

Raumann BE, Rould MA, Pabo CO, Sauer RT

Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.

Transcription of the ant gene during lytic growth of bacteriophage P22 (ref. 1)

is regulated by the cooperative binding of two Arc repressor dimers to a

21-base-pair operator site. Here we report the co-crystal structure of

this Arc tetramer-operator complex at 2.6 A resolution. As expected from

genetic and structural studies and from the co-crystal structure of the

homologous Escherichia coli MetJ repressor, each Arc dimer uses an

antiparallel beta-sheet to recognize bases in the major groove. However,

the Arc and MetJ complexes differ in several important ways: the

beta-sheet-DNA interactions of Arc are far less symmetrical; DNA binding

by Arc is accompanied by important conformational changes in the

beta-sheet; and Arc uses a different part of its protein surface for

dimer-dimer interactions.

MeSH Terms:

Base Sequence

Crystallography, X-Ray

DNA/metabolism*

Models, Molecular

Molecular Sequence Data

Operator Regions (Genetics)

Protein Structure, Secondary

Repressor Proteins/chemistry*

Support, Non-U.S. Gov't

Support, U.S. Gov't, P.H.S.

Viral Proteins/chemistry*

Substances:

DNA

Viral Proteins

Repressor Proteins

phage repressor proteins