1PK3

Scm SAM domain

1PK3 の概要

• エントリーDOI: 10.2210/pdb1pk3/pdb
• 関連するPDBエントリー: 1PK1
• 分子名称: Sex comb on midleg CG9495-PA, BETA-MERCAPTOETHANOL (3 entities in total)
• 機能のキーワード: sam domain, polymer, transcriptional repression, transcription repression
• 由来する生物種: Drosophila melanogaster (fruit fly)
• 細胞内の位置: Nucleus (Probable): Q9VHA0
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 31386.28

構造登録者

Kim, C.A.,Sawaya, M.R.,Cascio, D.,Kim, W.,Bowie, J.U. (登録日: 2003-06-04, 公開日: 2005-02-15, 最終更新日: 2024-02-14)

主引用文献

Kim, C.A.,Sawaya, M.R.,Cascio, D.,Kim, W.,Bowie, J.U.
Structural organization of a Sex-comb-on-midleg/polyhomeotic copolymer.
J.Biol.Chem., 280:27769-27775, 2005

PubMed Abstract: The polycomb group proteins are required for the stable maintenance of gene repression patterns established during development. They function as part of large multiprotein complexes created via a multitude of protein-protein interaction domains. Here we examine the interaction between the SAM domains of the polycomb group proteins polyhomeotic (Ph) and Sex-comb-on-midleg (Scm). Previously we showed that Ph-SAM polymerizes as a helical structure. We find that Scm-SAM also polymerizes, and a crystal structure reveals an architecture similar to the Ph-SAM polymer. These results suggest that Ph-SAM and Scm-SAM form a copolymer. Binding affinity measurements between Scm-SAM and Ph-SAM subunits in different orientations indicate a preference for the formation of a single junction copolymer. To provide a model of the copolymer, we determined the structure of the Ph-SAM/Scm-SAM junction. Similar binding modes are observed in both homo- and heterocomplex formation with minimal change in helix axis direction at the polymer joint. The copolymer model suggests that polymeric Scm complexes could extend beyond the local domains of polymeric Ph complexes on chromatin, possibly playing a role in long range repression.

PubMed: 15905166
DOI: 10.1074/jbc.M503055200

実験手法

X-RAY DIFFRACTION (1.85 Å)