Ans. of Queston 1

Searching words are Paco and Sauer

[Entrez-med-query]

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

PMID: 8107872, MUID: 94150708